CARBOHYDRATESCARBOHYDRATES

Medical BiochemistryMedical BiochemistryMolecular Principles of Structural Organization of CellsMolecular Principles of Structural Organization of Cells

CARBOHYDRATESCARBOHYDRATES – Are hydrated carbon molecules [CAre hydrated carbon molecules [CnnHH2n2nOOnn or (CH or (CH22O)O)nn], ], – They are virtually ubiquitous because they have such a wide range of They are virtually ubiquitous because they have such a wide range of

structures and functionsstructures and functions

Structure: Structure: – polyhydroxylated ketones, polyhydroxylated ketones, – polyhydroxylated aldehydes, or polyhydroxylated aldehydes, or – compounds that can be hydrolyzed into these compounds. compounds that can be hydrolyzed into these compounds.

A few of the A few of the functionsfunctions of carbohydrates include the following. of carbohydrates include the following.– provide the majority of provide the majority of energyenergy in most organisms (simple carbohydrates are in most organisms (simple carbohydrates are

sugars; complex carbohydrates can be broken down into simple sugars).sugars; complex carbohydrates can be broken down into simple sugars).– provide the provide the C atomsC atoms necessary for synthesis of lipids, proteins, nucleic acids necessary for synthesis of lipids, proteins, nucleic acids– enter in the enter in the structurestructure of complex compounds: of complex compounds:

mucopoliglucides, mucopoliglucides, glycolipids, glycolipids, coenzymes,coenzymes,comprise large portions of the nucleotides that form DNA and RNA (ribose, comprise large portions of the nucleotides that form DNA and RNA (ribose, deoxyribose) deoxyribose)

– serve as serve as metabolic intermediatesmetabolic intermediates (glucose-6-P, fructose-1,6-bisP). (glucose-6-P, fructose-1,6-bisP). – give give structurestructure to cell walls (in plants - cellulose) and cell membranes to cell walls (in plants - cellulose) and cell membranes – play a role in play a role in lubrication, cellular intercommunicationlubrication, cellular intercommunication, , immunityimmunity. .

CARBOHYDRATE CLASSIFICATION AND NOMENCLATURECARBOHYDRATE CLASSIFICATION AND NOMENCLATUREA.ClassificationA.Classification

MONOSES (Monosaccharides) MONOSES (Monosaccharides) such as glucose and fructose, are simple such as glucose and fructose, are simple sugars. They can be connected by glycosidic linkages to form more sugars. They can be connected by glycosidic linkages to form more complex compounds, glycosidescomplex compounds, glycosides

COMPLEX GLUCIDESCOMPLEX GLUCIDES::1.1. HomoglucidesHomoglucides

– OligosaccharidesOligosaccharides,, such as blood group antigens, are polymers such as blood group antigens, are polymers composed of 2-10 monosaccharide units. composed of 2-10 monosaccharide units. For example: For example: DisaccharidesDisaccharides, such as maltose and sucrose, can he , such as maltose and sucrose, can he hydrolyzed to 2 monoses, hydrolyzed to 2 monoses, trisaccharides trisaccharides to 3 monosesto 3 monoses, , tetrasaccharides tetrasaccharides to 4 monoses,…,…

– Polysaccharides, such as starch and cellulose, are polymers and cellulose, are polymers composed of >10 monosaccharides. composed of >10 monosaccharides.

2.2. Heteroglucides are formed of one carbohydrate and a noncarbohydrate Heteroglucides are formed of one carbohydrate and a noncarbohydrate componentcomponent

CARBOHYDRATE CLASSIFICATION AND NOMENCLATURECARBOHYDRATE CLASSIFICATION AND NOMENCLATURE

B. NomenclatureB. Nomenclature 1. 1. Carbon numbering systemCarbon numbering system. Monosaccharides are named . Monosaccharides are named according to a system that uses the number of carbons as according to a system that uses the number of carbons as the variable prefix followed by the variable prefix followed by -ose -ose as the suffix. as the suffix. In the general formula CIn the general formula CnnHH2n2nOOnn, n, n is the number of carbons. is the number of carbons.

a. Triose = 3 carbons a. Triose = 3 carbons b. Tetrose = 4 carbons b. Tetrose = 4 carbons c. c. Pentose = 5 carbons Pentose = 5 carbons d. Hexose = 6 carbons d. Hexose = 6 carbons

The carbons are numbered sequentiallyThe carbons are numbered sequentially

CARBOHYDRATE CLASSIFICATION AND NOMENCLATURECARBOHYDRATE CLASSIFICATION AND NOMENCLATURE

B. NomenclatureB. Nomenclature 2. 2. Reactive groupsReactive groups. The reactive group (aldehyde or ketone) on a . The reactive group (aldehyde or ketone) on a carbohydrate determines whether it is an aldose or a ketose. carbohydrate determines whether it is an aldose or a ketose.

– AldosesAldoses are monosaccharides with an aldehyde (-CH=O) group as are monosaccharides with an aldehyde (-CH=O) group as the reactive group (e.g. glucose). the reactive group (e.g. glucose).

– KetosesKetoses are monosaccharides with a ketone (>C=O) group as the are monosaccharides with a ketone (>C=O) group as the reactive group (e.g. fructose). reactive group (e.g. fructose).

The aldehyde or ketone group is on the carbon with the lowest possible The aldehyde or ketone group is on the carbon with the lowest possible number number

Monosaccharide and reactive-group nomenclature can be Monosaccharide and reactive-group nomenclature can be combined to designate compounds. combined to designate compounds.

For example, the sugar For example, the sugar glucose glucose is an aldohexose = a six-carbon is an aldohexose = a six-carbon monosaccharide monosaccharide (-hexose) (-hexose) containing an aldehyde group containing an aldehyde group (aldo-).(aldo-).

THE CLASSIFICATION OF THE CARBOHYDRATESTHE CLASSIFICATION OF THE CARBOHYDRATES ALDOSESALDOSES - C = O - C = O

functional Hfunctional H carbonyl carbonyl group group KETOSES > KETOSES > C = OC = O   MONOSES MONOSES TRIOSES TRIOSES (C = 3) glyceraldehyde, (C = 3) glyceraldehyde, (MONOSACCHARIDES, (MONOSACCHARIDES, number number TETROSES TETROSES (C = 4)(C = 4) SIMPLE SACCHARIDESSIMPLE SACCHARIDES of carbon of carbon PENTOSES PENTOSES (C = 5) ribose, deoxyribose (C = 5) ribose, deoxyribose SIMPLE GLUCIDES) SIMPLE GLUCIDES) atomsatoms HEXOSES HEXOSES (C = 6) glucose,galactose,fructose(C = 6) glucose,galactose,fructose HEPTOSES HEPTOSES (C = 7)(C = 7) MONOSES DERIVATIVESMONOSES DERIVATIVESCARBOHYDRATESCARBOHYDRATES (SUGARS, (SUGARS, URONIC ACIDSURONIC ACIDS AMINOGLUCIDESAMINOGLUCIDES PHOSPHOESTERSPHOSPHOESTERS SACCHARIDES, SACCHARIDES, (glucuronic, (glucosamine (glucose-6-phosphate,(glucuronic, (glucosamine (glucose-6-phosphate, GLUCIDES) GLUCIDES) galacturonic) galactosamine) fructose-1,6-diphosphate)galacturonic) galactosamine) fructose-1,6-diphosphate) DIGLUCIDES DIGLUCIDES maltose, lactose, sucrosemaltose, lactose, sucrose OLYGOGLUCIDESOLYGOGLUCIDES TRIGLUCIDES TRIGLUCIDES [2-6(10) monoses] [2-6(10) monoses] TETRAGLUCIDESTETRAGLUCIDES HOMOGLUCIDESHOMOGLUCIDES etc. etc. (HOMOGENEOUS (HOMOGENEOUS POLYGLUCIDESPOLYGLUCIDES Starch, Starch, CARBOHYDRATES)CARBOHYDRATES) ( (10 monoses) Glycogen10 monoses) Glycogen (only oses) Cellulose(only oses) Cellulose COMPLEXCOMPLEX CARBOHYDRATESCARBOHYDRATES HETEROGENEOUS HETEROGENEOUS Mucopolyglucides,Mucopolyglucides, CARBOHYDRATES CARBOHYDRATES Glycolipids,Glycolipids, (carbohydrate component + Glycoproteins,(carbohydrate component + Glycoproteins, noncarbohydrate component) etc.noncarbohydrate component) etc.

  

STRUCTURES – STRUCTURES – OPEN CHAIN FORMSOPEN CHAIN FORMS

Monoses areMonoses are– polyhydroxylated ketonespolyhydroxylated ketones– polyhydroxylated aldehydespolyhydroxylated aldehydes

IsomersIsomers are compounds with the same chemical formula but with different are compounds with the same chemical formula but with different structural formulastructural formula– Function isomersFunction isomers: glucose : glucose aldehydealdehyde function and fructose function and fructose ketoketo function function– Optical isomers (D Optical isomers (D andand L) L) oror enantiomers enantiomers– Epimers are two isomers with conformations that are different only at are two isomers with conformations that are different only at

one carbon atomone carbon atom. .

All monosaccharides (simple sugars) contain at least one All monosaccharides (simple sugars) contain at least one asymmetric carbonasymmetric carbon (a carbon bonded to four different atoms or groups of atoms). (a carbon bonded to four different atoms or groups of atoms).

In glucose, carbons 2—5 (C2—C5) are asymmetric. In glucose, carbons 2—5 (C2—C5) are asymmetric. Because of this carbon asymmetry, the sugars are Because of this carbon asymmetry, the sugars are optically activeoptically active, , and are and are

namednamed enantiomers:enantiomers: – ConfigurationConfiguration. .

The simplest carbohydrates are the trioses, such as glyceraldehyde, The simplest carbohydrates are the trioses, such as glyceraldehyde, which has which has two optically active formstwo optically active forms designated designated LL and and DD

– NomenclatureNomenclature. For the purposes of nomenclature, other sugars are . For the purposes of nomenclature, other sugars are considered to be derived from glyceraldehyde. Thus, a D-sugar is one considered to be derived from glyceraldehyde. Thus, a D-sugar is one that matches the configuration of D-glyceraldehyde around the that matches the configuration of D-glyceraldehyde around the asymmetric carbon that is the farthest from the aldehyde or ketone asymmetric carbon that is the farthest from the aldehyde or ketone group. An L-sugar correspondingly matches L-glyceraldehyde.group. An L-sugar correspondingly matches L-glyceraldehyde.

D-glyceraldehyde

                       

L-glyceraldehyde

EnantiomersEnantiomers are isomers are isomers that are mirror images.that are mirror images.

As mirror images, As mirror images, enantiomers rotate the enantiomers rotate the same plane of polarized same plane of polarized light to exactly the same light to exactly the same extent, but they do this in extent, but they do this in opposite directions, when opposite directions, when they are in aqueous they are in aqueous solution. solution.

L-glucose D-glucose

They have identical physical properties except for the direction of They have identical physical properties except for the direction of rotation of plane-polarized light.rotation of plane-polarized light.

If a plane of polarized light is rotated to the right (clockwise), If a plane of polarized light is rotated to the right (clockwise), the compound is the compound is dextrorotatorydextrorotatory. . If a plane of polarized light is rotated to the left (counterclockwise), If a plane of polarized light is rotated to the left (counterclockwise),

the compound is the compound is levorotatorylevorotatory..

EpimersEpimers are two isomers with conformations that are are two isomers with conformations that are different only at one carbon atom. different only at one carbon atom. – Glucose and Mannose are epimers at C2Glucose and Mannose are epimers at C2– Glucose and Galactose are epimers at C4Glucose and Galactose are epimers at C4

mannosemannose glucose glucose galactosegalactose

CHO

C HHO

C HHO

C OHH

C OHH

CH2OH

H

CHO

C OH

C HHO

C HHO

C OHH

CH2OH

CHO

C OHH

C HHO

C OHH

C OHH

CH2OH

STRUCTURE – STRUCTURE – CYCLIC FORMCYCLIC FORM

In aqueous solution monoses exist in chain form or a spontaneous reaction In aqueous solution monoses exist in chain form or a spontaneous reaction takes place between one of the hydroxyl groups and the carbonyl group takes place between one of the hydroxyl groups and the carbonyl group leading to cyclic structures leading to cyclic structures – five members = 4 carbon atoms and 1 oxygen atom (five members = 4 carbon atoms and 1 oxygen atom (furanosefuranose) ) – six members = 5 carbon atoms and 1 oxygen atom (six members = 5 carbon atoms and 1 oxygen atom (pyranosepyranose))

Pentoses, such as ribose, Pentoses, such as ribose,

form a five-membered ring form a five-membered ring

(ribo(ribofuranosefuranose))

Hexoses, such as glucose or galactose, Hexoses, such as glucose or galactose,

form a five-membered ring form a five-membered ring

(gluco(glucofuranosefuranose))

or six-membered ring or six-membered ring

(gluco(glucopyranosepyranose))

H O

OH OH

H

OHH

OH

CH2-OH

HH

CH2-OH

H

OH

H

OH OH

H HO

CH-OH

OH

H

OH

H OH

OH HO

CH2-OH

HemiacetalsHemiacetals can occur in linear or cyclic forms. can occur in linear or cyclic forms. When an alcohol reacts with an aldehyde, linear, unstable When an alcohol reacts with an aldehyde, linear, unstable compounds occur: intermolecular hemiacetalscompounds occur: intermolecular hemiacetals– Cyclic hemiacetals are formed by similar intramolecular reactions. Cyclic hemiacetals are formed by similar intramolecular reactions.

In glucose, the hydroxyl group on C-5 can react intramolecularly In glucose, the hydroxyl group on C-5 can react intramolecularly with the carbonyl group on C-1 to form a stable with the carbonyl group on C-1 to form a stable cyclic hemiacetalcyclic hemiacetal. .

                                       

AnomericAnomeric carbon is the carbon is the new asymmetric carbonnew asymmetric carbon (C-1 in glucose) (C-1 in glucose) that is created by cyclization at the carbon bound to oxygen in that is created by cyclization at the carbon bound to oxygen in hemiacetalhemiacetal formation, with essential role in formation, with essential role in reducing propertiesreducing properties of of glucides.glucides.a. If the hydroxyl on the anomeric carbon is a. If the hydroxyl on the anomeric carbon is belowbelow the plane of the the plane of the

ring, it is in the ring, it is in the α positionα position. . b. If the hydroxyl on the anomeric carbon is b. If the hydroxyl on the anomeric carbon is aboveabove the plane of the the plane of the

ring, it is in the ring, it is in the ββ positionposition. .

Mutarotation is the process by which α and βMutarotation is the process by which α and β sugars, in solution, sugars, in solution, slowly change into an equilibrated mixture of both. slowly change into an equilibrated mixture of both.

1. α-D-Glucopyranose (62%); 1. α-D-Glucopyranose (62%);

2. β-D-Glucopyranose (38%); 2. β-D-Glucopyranose (38%);

3. α-D-Glucofuranose (trace); 3. α-D-Glucofuranose (trace);

4. β-D-Glucofuranose (trace);4. β-D-Glucofuranose (trace);

5. Linear D-Glucose (0.01%).5. Linear D-Glucose (0.01%).

H O

OH OH

H

OHH

OH

CH2-OH

HH H O

OH H

H

OHH

OH

CH2-OH

HOH

Glucose Glucose

CHO

C OHH

C HHO

C OHH

C OHH

CH2OH

H O

OH OH

H

OHH

OH

CH2-OH

HH H O

OH H

H

OHH

OH

CH2-OH

HOH

CH-OH

OH

H

OH

H OH

OH HO

CH2-OH

CH-OH

H

OH

OH

H OH

OH HO

CH2-OH

αα-D-gluco-D-glucopyranosepyranose ββ-D-gluco-D-glucopyranosepyranose

αα-D-gluco-D-glucofuranosefuranose ββ-D-gluco-D-glucofuranosefuranose

GalactoseGalactose

H

CHO

C OH

C HHO

C HHO

C OHH

CH2OH

H

CHO

C OH

C HHO

C HHO

C OHH

CH2OH

H

CHO

C OH

C HHO

C HHO

C OHH

CH2OH

OH O

H OH

H

OHH

OH

CH2-OH

HH

OH O

H H

H

OHH

OH

CH2-OH

HOH

αα-galacto-galactopyranosepyranose

ββ-galacto-galactopyranosepyranose

FructoseFructose

CH2-OH

C O

C HHO

C OHH

C OHH

CH2OH

CH2-OH

OH

CH2-OH

H

OH H

H OHO

CH2-OH

CH2-OH

OH

H

OH H

H OHO

αα-fructo-fructofuranosefuranose

ββ-fructo-fructofuranosefuranose

GLYCOSIDIC LINKAGESGLYCOSIDIC LINKAGES

A sugar can react with an alcohol to form an acetal known as a A sugar can react with an alcohol to form an acetal known as a glycoside.glycoside.

– If the sugar residue is glucose, the derivative is a If the sugar residue is glucose, the derivative is a glucosideglucoside; ; – if the residue is fructose, the derivative is a if the residue is fructose, the derivative is a fructosidefructoside. . – a residue of galactose results in a a residue of galactose results in a galactosidegalactoside derivative. derivative.

When the side chain (R) is another sugar, the glycoside is a When the side chain (R) is another sugar, the glycoside is a disaccharidedisaccharide..

e.g. maltose = e.g. maltose = αα-D-glucopyranosyl--D-glucopyranosyl-αα-D-glucopyranoside -D-glucopyranoside sucrose sucrose = = αα-D-glucopyranosyl-β-D-fructofuranoside-D-glucopyranosyl-β-D-fructofuranoside

If R is already a disaccharide, the glycoside is a If R is already a disaccharide, the glycoside is a trisaccharide trisaccharide and so and so forth.forth.

H O

OH

H

OHH

OH

CH2-OH

HH H O

OH

H

OHH

OH

CH2-OH

HH

O

CARBOHYDRATES CARBOHYDRATES WITH IMPORTANCE IN WITH IMPORTANCE IN

MEDICINE AND PHARMACYMEDICINE AND PHARMACY

TRIOSESTRIOSES

glyceraldehyde dihydroxyacetoneglyceraldehyde dihydroxyacetone

Result as intermediary metabolites (in phosphoric esters Result as intermediary metabolites (in phosphoric esters form) in the reactions of carbohydrate degradation form) in the reactions of carbohydrate degradation (glycolysis)(glycolysis)

HC O

C OHH

CH2OH

CH2OH

C O

CH2OH

PENTOSESPENTOSES

Exogenous origin (food) Exogenous origin (food) In the cell, have higher metabolic stability than hexoses In the cell, have higher metabolic stability than hexoses

D-ribose (anomer D-ribose (anomer β)β): : – Does not exist free in the cellDoes not exist free in the cell– Biological importance: as phosphate ester enters in the structure Biological importance: as phosphate ester enters in the structure

of nucleosides, nucleotides, RNA, coenzymes, metabolic of nucleosides, nucleotides, RNA, coenzymes, metabolic intermediates in pentose-phosphate cycleintermediates in pentose-phosphate cycle

2-Deoxy-D-ribose (anomer 2-Deoxy-D-ribose (anomer β)β)– In the structure of deoxyribonucleosides and nucleotides, In the structure of deoxyribonucleosides and nucleotides,

structural monomers of deoxyribonucleic acid (DNA)structural monomers of deoxyribonucleic acid (DNA)

                         

CHO

C OHH

C OHH

C OHH

CH2OH

CH2-OH

H

OH

H

OH OH

H HO

CHO

C HH

C OHH

C OHH

CH2OH

CH2-OH

H

OH

H

OH H

H HO

ββ-D-ribose-D-ribose ββ--2-deoxy2-deoxy-D-ribose-D-ribose

HEXOSESHEXOSES

AldohexosesAldohexoses– glucose = Glc = G (dextrose, blood sugar, grape sugar), glucose = Glc = G (dextrose, blood sugar, grape sugar), – galactose = Gal (cerebrose), galactose = Gal (cerebrose), – mannose = Manmannose = Man

KetohexoseKetohexose– fructose = Fru, F (levulose, fruit sugarfructose = Fru, F (levulose, fruit sugar))

GLUCOSE (Glc, G)GLUCOSE (Glc, G)Ubiquitous in the animal and plant organismsUbiquitous in the animal and plant organismsThe main ose in the human organismThe main ose in the human organismLocationLocation– In all the cells and fluids of the organism In all the cells and fluids of the organism

except the urine except the urine

FunctionsFunctions

– energeticenergetic: through degradation (glycolysis) energy is generated as ATP: through degradation (glycolysis) energy is generated as ATP

– it enters in the it enters in the structurestructure of of

diglucides: maltose, isomaltose, lactose, sucrose, celobiosediglucides: maltose, isomaltose, lactose, sucrose, celobiose

polyglucides: starch, glycogen, cellulosepolyglucides: starch, glycogen, cellulose

– by oxidation in the liver it is transformed in by oxidation in the liver it is transformed in glucuronic acidglucuronic acid with important role in with important role in detoxifyingdetoxifying the organism. the organism.

- - In the blood it exists in a constant interval of 65-110 mg/dl (glycemia); In the blood it exists in a constant interval of 65-110 mg/dl (glycemia); maintained mainly by the antagonistic action of 2 pancreatic hormones:maintained mainly by the antagonistic action of 2 pancreatic hormones:

•insulin - hypoglicemiantinsulin - hypoglicemiant

•glucagon – hyperglycemiantglucagon – hyperglycemiant

The increased values of glycemia are present in diabetes mellitus and endocrine The increased values of glycemia are present in diabetes mellitus and endocrine diseasesdiseases

CHO

C OHH

C HHO

C OHH

C OHH

CH2OH

H O

OH OH

H

OHH

OH

CH2-OH

HH

GALACTOSE (Gal)GALACTOSE (Gal)

Location: Location: it exists in reduced amount in blood, CSF, urineit exists in reduced amount in blood, CSF, urine

Function:Function:– With glucose forms With glucose forms lactoselactose, the sugar in the milk, the sugar in the milk– Enters in the structure of Enters in the structure of complex lipidscomplex lipids in the brain (cerebrosides, in the brain (cerebrosides, sulfatides, gangliosides)sulfatides, gangliosides)–By oxydation in the liver forms the By oxydation in the liver forms the galacturonic acidgalacturonic acid that enters in the that enters in the structure of mucopolyglucides (complex carbohydrates)structure of mucopolyglucides (complex carbohydrates)

H

CHO

C OH

C HHO

C HHO

C OHH

CH2OH

OH O

H H

H

OHH

OH

CH2-OH

HOH

FRUCTOSE (Fru, F)FRUCTOSE (Fru, F)

The sweetest of all sugarsThe sweetest of all sugars

Structure: ketohexose Structure: ketohexose – pyranose in free form and pyranose in free form and

– furanose in all natural derivativesfuranose in all natural derivatives

Location:Location:– free in the secretion of seminal vesiclesfree in the secretion of seminal vesicles

– combined with glucose forms the sucrose, the sugar in the fruitscombined with glucose forms the sucrose, the sugar in the fruits

– as phosphoric ester is an intermediate in the metabolism of glucose as phosphoric ester is an intermediate in the metabolism of glucose (glycolysis and pentose-phosphate cycle), (glycolysis and pentose-phosphate cycle),

CH2-OH

C O

C HHO

C OHH

C OHH

CH2OH

CH2-OH

OH

CH2-OH

H

OH H

H OHO

CARBOHYDRATES DERIVATIVES CARBOHYDRATES DERIVATIVES 1. URONIC ACIDS1. URONIC ACIDS

Are produced by the oxydation of the Are produced by the oxydation of the aldehyde carbon, the hydroxyl carbon or aldehyde carbon, the hydroxyl carbon or bothbothGlucuronic acid (GlcA, GlcUA)Glucuronic acid (GlcA, GlcUA)– pyranose form in natural productspyranose form in natural products– component of proteoglycanscomponent of proteoglycans– process of detoxification of normal process of detoxification of normal

biological compounds, waste products or biological compounds, waste products or toxins (phenols, alcohols, amines, amides, toxins (phenols, alcohols, amines, amides, etc)etc)

Galacturonic acid (GalA, GalUA)Galacturonic acid (GalA, GalUA)– component of glucosaminoglycanscomponent of glucosaminoglycans– components of pectins, plant gums, components of pectins, plant gums,

mucilagesmucilages– in the bacterial polysaccharidesin the bacterial polysaccharides

H O

OH H

H

OHH

OH

COOH

HOH

OH O

H H

H

OHH

OH

COOH

HOH

CARBOHYDRATES DERIVATIVES CARBOHYDRATES DERIVATIVES 2. AMINOSUGARS / AMINOGLUCIDES2. AMINOSUGARS / AMINOGLUCIDES

A hydroxyl group is replaced with A hydroxyl group is replaced with amino or acetylamino groupamino or acetylamino group

D-glucosamine (GlcND-glucosamine (GlcN, chitosamine) as , chitosamine) as – N-acetylglucosamine (GlcNAc) is the product of the N-acetylglucosamine (GlcNAc) is the product of the

hydrolysis of hyaluronic acid and chitin, the major hydrolysis of hyaluronic acid and chitin, the major component of the shells of insects and crustaceans; component of the shells of insects and crustaceans; heparin, blood-group substances heparin, blood-group substances

– N-acetyl-muramic acid is part of the bacterial N-acetyl-muramic acid is part of the bacterial membrane membrane

D-galactosamineD-galactosamine as as – D-galactosamine sulfate found in polysaccharides of D-galactosamine sulfate found in polysaccharides of

cartilage, chondroitin sulfate, cartilage, chondroitin sulfate, – N-acetyl galactosamineN-acetyl galactosamine

D-mannosamineD-mannosamine as N-acetyl-neuraminic acid (AcNeu, as N-acetyl-neuraminic acid (AcNeu, NeuAc,sialic acid) is an essential component of the NeuAc,sialic acid) is an essential component of the glycoproteins and glycolipids in the brain, erythrocyte glycoproteins and glycolipids in the brain, erythrocyte stroma, bacterial cell membranestroma, bacterial cell membrane

H O

OH OH

H

NH2H

OH

CH2-OH

HH

H O

OH OH

H

NH-CO-CH3H

OH

CH2-OH

HH

OH O

H OH

H

NH-SO3HH

OH

CH2-OH

HH

OH O

H H

H

NH-CO-CH3H

OH

CH2-OH

HOH

CARBOHYDRATES DERIVATIVES CARBOHYDRATES DERIVATIVES 3. PHOSPHORIC ESTERS3. PHOSPHORIC ESTERS

Are formed from the reaction of phosphoric acid with a hydroxyl Are formed from the reaction of phosphoric acid with a hydroxyl group of the sugar. Phosphorylation is the initial step of the group of the sugar. Phosphorylation is the initial step of the metabolism of sugars.metabolism of sugars.

They are metabolic intermediates They are metabolic intermediates

Examples:Examples:– glyceraldehyde-3-P, dihydroxyacetone-1-P, dihydroxyacetone-3-Pglyceraldehyde-3-P, dihydroxyacetone-1-P, dihydroxyacetone-3-P

                             

HC O

C OHH

CH2-O-PO3H2

CH2-O-PO3H2

C O

CH2OH

CH2OH

C O

CH2-O-PO3H2

– ribose-5-P ribose-3,5-bisPribose-5-P ribose-3,5-bisP

– glucose-1-P glucose-6-Pglucose-1-P glucose-6-P

– fructose-1-P fructose-1,6-bisPfructose-1-P fructose-1,6-bisP

CH2-O-PO3H2

H

OH

H

OH OH

H HO

CH2-O-PO3H2

H

OH

H

O-PO3H2OH

H HO

H O

OH O-PO3H2

H

OHH

OH

CH2-OH

HH H O

OH OH

H

OHH

OH

CH2-O-PO3H2

HH

CH2-O-PO3H2

OH

CH2-OH

H

OH H

H OH

O

CH2-O-PO3H2H

OH

CH2-O-PO3H2H

H

OH H

H OHO

BIOCHEMICAL IMPORTANCE OF MONOSESBIOCHEMICAL IMPORTANCE OF MONOSES

Source of energySource of energy in the presence or absence of oxygen (aerobic or in the presence or absence of oxygen (aerobic or anaerobic glycolysis)anaerobic glycolysis)

Plastic functionPlastic function as they are involved as derivatives in the buildup of as they are involved as derivatives in the buildup of diverse biological molecules (nucleosides, nucleotides, coenzymes, diverse biological molecules (nucleosides, nucleotides, coenzymes, glycolipids, glycoproteins)glycolipids, glycoproteins)

OLYGOSACCHARIDES / OLYGOGLUCIDESOLYGOSACCHARIDES / OLYGOGLUCIDES

Are complex glucides resulting from the condensation of Are complex glucides resulting from the condensation of 2-6(10) identical 2-6(10) identical osesoses

Depending on the number of oses they can be: disaccharides (2 oses), Depending on the number of oses they can be: disaccharides (2 oses), trisaccharides (3 oses), tetrasaccharides (4 oses)…trisaccharides (3 oses), tetrasaccharides (4 oses)…

Depending on the mechanism of water elimination they can have reducing Depending on the mechanism of water elimination they can have reducing properties or not:properties or not:– Reducing disaccaridesReducing disaccarides are formed when the molecule of H are formed when the molecule of H22O is eliminated O is eliminated

between the hemiacetalic –OH of one ose and an alcoholic –OH of the second between the hemiacetalic –OH of one ose and an alcoholic –OH of the second ose; the hemiacetalic or hemiketalic –OH of the second ose rests free. This ose; the hemiacetalic or hemiketalic –OH of the second ose rests free. This type of bond is called monocarbonylic or type of bond is called monocarbonylic or glycosidic bondglycosidic bond oriented oriented αα or or ββ (e.g. (e.g. maltose, isomaltose, lactose, cellobiose)maltose, isomaltose, lactose, cellobiose)

– Nonreducing disaccharidesNonreducing disaccharides are formed by the elimination of H are formed by the elimination of H22O between the O between the

two -OH hemiacetalic or hemicetalic, blocking both reducing groups in the bond two -OH hemiacetalic or hemicetalic, blocking both reducing groups in the bond (e.g. sucrose)(e.g. sucrose)

REDUCING DISACCHARIDESREDUCING DISACCHARIDES

1. MALTOSE1. MALTOSEStructure:Structure:– It results from the condensation of 2 It results from the condensation of 2 α-glucoseα-glucose– The bond in maltose is between C1 and C4 (The bond in maltose is between C1 and C4 (α-1,4-glycosidicα-1,4-glycosidic configuration) configuration) – It possesses an unattached anomeric carbon atom, thus it is a It possesses an unattached anomeric carbon atom, thus it is a reducingreducing

sugar. sugar.

Role: Role: – It exists in the structure of starch and glycogen from the food, resulting It exists in the structure of starch and glycogen from the food, resulting

from their partial hydrolysis, catalyzed by the from their partial hydrolysis, catalyzed by the amylaseamylase from saliva and from saliva and pancreatic juice pancreatic juice

– It is hydrolyzed in the intestine, under the action of It is hydrolyzed in the intestine, under the action of maltasemaltase

H O

OH

H

OHH

OH

CH2-OH

HH H O

OH

H

OHH

OH

CH2-OH

HH

O

H O

OH O

H

OHH

OH

CH2-OH

HH

H O

OH

H

OHH

OH

CH2

HH

OH

REDUCING DISACCHARIDESREDUCING DISACCHARIDES

2. 2. ISOMALTOSE ISOMALTOSE Structure:Structure:– It results from the condensation of 2 It results from the condensation of 2 α-glucoseα-glucose– The bond is between CThe bond is between C11-C-C66 ( (α-1,6-glycosidic)α-1,6-glycosidic)– It possesses a free hemiacetalic –OH, thus it is a It possesses a free hemiacetalic –OH, thus it is a reducingreducing sugar sugar

In the structure of amylopectin and glycogenIn the structure of amylopectin and glycogen

3. 3. CELLOBIOSECELLOBIOSEStructure:Structure:– It results from the condensation of 2 It results from the condensation of 2 ββ-glucose-glucose– The bond is between C1-C4 (The bond is between C1-C4 (ββ-1,4-glycosidic-1,4-glycosidic))– The free hemiacetalic The free hemiacetalic ββ-OH gives -OH gives reducingreducing properties properties

It results from cellulose hydrolysis It results from cellulose hydrolysis It is hydrolyzed in the digestive tract of herbivorous catalyzed by It is hydrolyzed in the digestive tract of herbivorous catalyzed by cellobiasecellobiase produced by the microflora produced by the microflora

H O

OH H

H

OHH

OH

CH2-OH

HH O

H

H

OHH

OH

CH2-OH

HOH

O

REDUCING DISACCHARIDES REDUCING DISACCHARIDES

4. LACTOSE4. LACTOSE

milk sugar, slightly sweetmilk sugar, slightly sweet

Structure:Structure:– formed of formed of ββ-Galactose-Galactose and and αα-Glucose-Glucose

– bond between C1-C4 bond between C1-C4 ((ββ-1,4)-1,4)

– αα-OH hemiacetalic is free (-OH hemiacetalic is free (reducingreducing))

Synthesized by the mammary glandsSynthesized by the mammary glands

Exists in milk as free diglucide (2-8%)Exists in milk as free diglucide (2-8%)

Its hydrolysis is catalyzed by Its hydrolysis is catalyzed by lactaselactase, in the intestine; the , in the intestine; the ββ-Gal-Gal is is absorbed and transported to the liver where it is converted in absorbed and transported to the liver where it is converted in αα--Glu; Glu; if the enzyme is deficient the Gal is accumulated (galactosemia = if the enzyme is deficient the Gal is accumulated (galactosemia = genetic disease)genetic disease)

OH O

H H

H

OHH

OH

CH2-OH

HH O

OH

H

OHH

OH

CH2-OH

HH

O

NONREDUCING DISACCHARIDES NONREDUCING DISACCHARIDES

SUCROSESUCROSE

In contrast to the linkages in most other simple carbohydrates, In contrast to the linkages in most other simple carbohydrates, the oxygen bridge between the oxygen bridge between α-Glucoseα-Glucose and and ββ-Fructose-Fructose is between is between the hemiacetalic –OH at Cthe hemiacetalic –OH at C11 of Glc and hemicetalic –OH at C of Glc and hemicetalic –OH at C22 of of Fru (Fru (α,α,ββ-1,2-glycosidic-1,2-glycosidic linkage). linkage). Consequently, there is no free Consequently, there is no free hemiacetalic or hemicetalic -OH hemiacetalic or hemicetalic -OH group in sucrose.Therefore, this disaccharide is group in sucrose.Therefore, this disaccharide is not a reducing not a reducing sugarsugar. For example, it will not reduce an alkaline copper reagent . For example, it will not reduce an alkaline copper reagent such as Fehling’s solution.such as Fehling’s solution. Exists in the sugar beet and cane; it is very solubleExists in the sugar beet and cane; it is very solubleIts hydrolysis catalyzed by Its hydrolysis catalyzed by sucrasesucrase generates the 2 oses generates the 2 oses

H

OH

H

OHH

OH

CH2-OH

HH

CH2-OH

CH2-OHH

OH H

H OHO

O

POLYSACCHARIDES/POLYGLUCIDES/GLYCANSPOLYSACCHARIDES/POLYGLUCIDES/GLYCANS

Classification:Classification:– HomoglycansHomoglycans – products of polycondensation of – products of polycondensation of one typeone type of ose: of ose:

glucose glucose → glycans : starch, glycogen, cellulose→ glycans : starch, glycogen, cellulose

galactose → galactosans galactose → galactosans

mannose → mannans, mannose → mannans,

arabinose →arabinans.arabinose →arabinans.

– HeteroglycansHeteroglycans – products of polycondensation of – products of polycondensation of more typesmore types of of structural units:structural units:

Mucopolyglucides components of proteoglycansMucopolyglucides components of proteoglycans

Bacterial polyglucidesBacterial polyglucides

HOMOGENEOUS POLYGLUCIDESHOMOGENEOUS POLYGLUCIDES

Result of the condensation of a great number of identical osesResult of the condensation of a great number of identical oses

The repeating unit is The repeating unit is – maltose in starch and glycogenmaltose in starch and glycogen

– cellobiose in cellulosecellobiose in cellulose

Role: reserve of energyRole: reserve of energy

Structure: linear or branchedStructure: linear or branched

The hydrolysis catalyzed by hydrolases = glycosidases results in the The hydrolysis catalyzed by hydrolases = glycosidases results in the component osescomponent oses

Properties:Properties:– Hydrophilic - when placed in water they swell and then dissolve to form Hydrophilic - when placed in water they swell and then dissolve to form

colloidal solutions, very viscous, capable of gelationcolloidal solutions, very viscous, capable of gelation

HOMOGENEOUS HOMOGENEOUS POLYGLUCIDES POLYGLUCIDES 1. STARCH1. STARCH

is the storage form of glucose in plants, resulting from photosynthesisis the storage form of glucose in plants, resulting from photosynthesisis formed of grains with characteristic microscopic appearance for each is formed of grains with characteristic microscopic appearance for each plantplanthas amorphous structure, is insoluble in water; in hot water forms a pastehas amorphous structure, is insoluble in water; in hot water forms a pastehas weak reducing propertieshas weak reducing propertiesis identified in reaction with iodine (blue colour)is identified in reaction with iodine (blue colour)the enzyme catalyzed hydrolysis is progressive, generating intermediates the enzyme catalyzed hydrolysis is progressive, generating intermediates with smaller molecular mass (with smaller molecular mass (dextrinesdextrines) that have specific colours in ) that have specific colours in reaction with iodine: reaction with iodine: →→ amylodextrines (blue-violet) amylodextrines (blue-violet) →→ erythrodextrines erythrodextrines (red) (red) →→ flavodextrines (yellow) flavodextrines (yellow) →→ acrodextrines (colorless) acrodextrines (colorless) →→ maltose maltose →→ glucoseglucosethe repeating unit is the repeating unit is maltosemaltosethe grains are formed of amylose (20%) in the center and amylopectin (80%) as an the grains are formed of amylose (20%) in the center and amylopectin (80%) as an envelopeenvelope

AmyloseAmylose It is a linear unbranched polymer (M=10It is a linear unbranched polymer (M=1055) formed of 100-400 ) formed of 100-400 α-glucoseα-glucose moieties (as maltose) linked with moieties (as maltose) linked with α-1,4α-1,4-glycosidic bonds.-glycosidic bonds.

The chain has α-helix configuration (6 glucose each turn)The chain has α-helix configuration (6 glucose each turn)

It has hemiacetal –OH only at the end of the chain (It has hemiacetal –OH only at the end of the chain (weak reducingweak reducing properties)properties)

It is soluble in hot water forming coloidal solution; in cold water forms a gelIt is soluble in hot water forming coloidal solution; in cold water forms a gel

It is identified in reaction with iodine (blue colour)It is identified in reaction with iodine (blue colour)

H O

OH

H

OHH

OH

CH2-OH

HH H O

H

OHH

OH

CH2-OH

HH

O

H O

H

OHH

OH

CH2-OH

HH H O

H

OHH

OH

CH2-OH

HH

O

H O

H

OHH

OH

CH2-OH

HH H O

OHH

OHH

OH

CH2-OH

HH

OO O

Amylopectin Amylopectin It is a branched polymer (M=10It is a branched polymer (M=1066-10-1077)) of of α-glucoseα-glucose (10 000) linked with (10 000) linked with glycosidic bonds of 2 types:glycosidic bonds of 2 types:– α-1,4α-1,4-glycosidic linkages (maltose type) and-glycosidic linkages (maltose type) and– α-1,6α-1,6 (isomaltose type) branching points that occur at intervals of (isomaltose type) branching points that occur at intervals of

approximately approximately 16 α-D-glucose residues on the external chain and 16 α-D-glucose residues on the external chain and 10 residues on the internal chain10 residues on the internal chain

The hydrolysis in the digestive tract implies the catalytic activity of:The hydrolysis in the digestive tract implies the catalytic activity of:– α-amylaseα-amylase (salivary and pancreatic) acts on α-1,4 bonds in the middle of the (salivary and pancreatic) acts on α-1,4 bonds in the middle of the

chain chain → dextrines → maltose → glucose→ dextrines → maltose → glucose– 1,6-α-glycosidase1,6-α-glycosidase acts on α-1,6 bonds acts on α-1,6 bonds → amylose→ amylose– maltasemaltase acts on maltose acts on maltose → 2 → 2 α-α-glucose (absorbed in the intestine wall and glucose (absorbed in the intestine wall and

transported to the liver)transported to the liver)

H O

OH

H

OHH

OH

CH2-OH

HH H O

H

OHH

OH

CH2-OH

HH

O

H O

OH

OHH

OH

CH2-OH

HH

O

H O

OH

H

OHH

OH

CH2-OH

HH H O

H

OHH

OH

CH2-OH

HH

O

H O

H

OHH

OH

CH2

HH H O

H

OHH

OH

CH2-OH

HH

O

H O

H

OHH

OH

CH2-OH

HH H O

OHH

OHH

OH

CH2-OH

HH

OO O

HOMOGENEOUS POLYSACCHARIDES HOMOGENEOUS POLYSACCHARIDES 2. GLYCOGEN2. GLYCOGENIt is the major storage form of carbohydrate in animals (liver and muscle). It is the major storage form of carbohydrate in animals (liver and muscle). It is a highly branched form of amylopectin (M=10It is a highly branched form of amylopectin (M=1066-10-1077): ): – α-1,4α-1,4-glycosidic linkages -glycosidic linkages – α-1,6α-1,6 branching points occur every 6-7 α-glucose residues in the external and 3 branching points occur every 6-7 α-glucose residues in the external and 3

residues in the inner chains.residues in the inner chains.The hydrolysis of exogeneous glycogen is similar with the one of starch. The hydrolysis of exogeneous glycogen is similar with the one of starch. The endogeneous glycogen is transformed by:The endogeneous glycogen is transformed by:– phosphorolysis, catalysed by phosphorylase that act on α-1,4 bonds beginning phosphorolysis, catalysed by phosphorylase that act on α-1,4 bonds beginning

with the nonreducing end of the chain with the nonreducing end of the chain → G-1-P→ G-1-P::In the liver, G-1-P is used to maintain the glycemia constant In the liver, G-1-P is used to maintain the glycemia constant In the muscle G-1-P In the muscle G-1-P → G-6-P→ G-6-P used to provide the energy necessary for muscular used to provide the energy necessary for muscular contraction (glycolysis)contraction (glycolysis)

– α-1,6-glycosylase that act on α-1,6 bonds.α-1,6-glycosylase that act on α-1,6 bonds.

H O

OH

H

OHH

OH

CH2-OH

HH H O

H

OHH

OH

CH2-OH

HH

O

H O

OH

OHH

OH

CH2-OH

HH

O

H O

OH

H

OHH

OH

CH2-OH

HH H O

H

OHH

OH

CH2-OH

HH

O

H O

H

OHH

OH

CH2

HH H O

H

OHH

OH

CH2-OH

HH

O

H O

H

OHH

OH

CH2-OH

HH H O

OHH

OHH

OH

CH2-OH

HH

OO O

HOMOGENEOUS POLYSACCHARIDES HOMOGENEOUS POLYSACCHARIDES 3. CELLULOSE3. CELLULOSE

It is a structural polysaccharide of plant cells (M= 10It is a structural polysaccharide of plant cells (M= 1066).).

It is composed of linear (unbranched) chains of β-glucose units It is composed of linear (unbranched) chains of β-glucose units ((cellobiosecellobiose) joined by ) joined by β-1,4β-1,4-glycosidic linkages. -glycosidic linkages.

The chains can form fibersThe chains can form fibers

The hydrolysis of β-1,4-glycosidic bonds is catalysed by The hydrolysis of β-1,4-glycosidic bonds is catalysed by cellulasecellulase or or cellobiasecellobiase that do not exist in the human digestive tract that do not exist in the human digestive tract

Although cellulose forms a part of the human diet (in vegetables, Although cellulose forms a part of the human diet (in vegetables, fruit), only a very small amount is transformed under the action of fruit), only a very small amount is transformed under the action of the intestinal microflorathe intestinal microflora

It is important for the maintenance of the intestinal movements, as a It is important for the maintenance of the intestinal movements, as a protective mean against the cancer of the colon.protective mean against the cancer of the colon.

H O

OH

H

OHH

OH

CH2-OH

HH O

HH

OHH

OH

CH2-OH

HO

H O

HH

OHH

OH

CH2-OH

HH O

HH

OHH

OH

CH2-OH

HO

H O

H

H

OHH

OH

CH2-OH

HH O

HH

OHH

OH

CH2-OH

HOH

OOO

HETEROGLUCIDES/HETEROGLUCIDES/GLYCOSAMINOGLYCANS (GAGs)/PROTEOGLYCANSGLYCOSAMINOGLYCANS (GAGs)/PROTEOGLYCANS

Structure: – glucide component (C,H,O, N and/or S) 85-90% of molecular mass and– non glucide component (protein) in small amount, – linked by covalent or electrovalent bonds with the proteins (proteoglycans), except the hyaluronic acid (only polyglucide)– they form viscous solutions, mucus – the name mucopolyglucides refers to heteropolyglucides of animal origin

Classification: depending on the nature of glucide component :– acidic = hexozamine + uronic acid– neutral = only hexozamine

Acidic GAGsAcidic GAGs

l Structure: long unbranched polysaccharides containing repeating disaccharide units that contain hexosamine + uronic acid

The physiologically most important Acidic GAGs are – hyaluronic acid, – chondroitin sulfate, dermatan sulfate– heparin, heparan sulfate.

Location: found in the lubricating fluid of the joints and as components of cartilage, synovial fluid, vitreous humor,

bone, and heart valves.

1. Hyaluronic acid1. Hyaluronic acid

Structure: polyglucide macromolecule Structure: polyglucide macromolecule – Glucuronic acid + N-acetylglucozamine (Glucuronic acid + N-acetylglucozamine (ββ-1,3-bonds) = -1,3-bonds) = hyalobiuronic acidhyalobiuronic acid

– The repeated units are linked The repeated units are linked ββ-1,4-1,4-bonds-bonds

Location: embryonic tissue, conjunctive tissue, cartilage, cornea, vitreous Location: embryonic tissue, conjunctive tissue, cartilage, cornea, vitreous fluid, synovial fluid, umbilical cordfluid, synovial fluid, umbilical cord

Role: tissue cement, lubricant, shock protective; marked capacity for Role: tissue cement, lubricant, shock protective; marked capacity for binding water binding water

Biosynthesis in the fibroblasts in 2 daysBiosynthesis in the fibroblasts in 2 days

Depolymerized by Depolymerized by hyaluronidasehyaluronidase, , – that acts on that acts on ββ-1,4-bonds-1,4-bonds

– exists in the spermatozoa cap, venom, bacteriaexists in the spermatozoa cap, venom, bacteria

In the tissues there is an In the tissues there is an anti-hyaluronidaseanti-hyaluronidase (Physiologic Hyaluronidase (Physiologic Hyaluronidase Inhibitor = PHI)Inhibitor = PHI)

2. Chondroitin sulfates2. Chondroitin sulfates

Structure: it is a polyglucide macromolecule atached to protein, composed of :– β-D-glucuronate + N-acetylgalactosamine-4-sulfate or 6-sulfate (linked

β-1,3) = chondrosine– The units are linked β-1,4

Location: cartilage, bones, tendons, skin, aorta, corneaThe great number of negative charges = cations changing resins, regulating the cartilage matrix structure and the storage of minerals in the bone matrixThey are attached to proteins and associated with hyaluronic acid forming supra-molecular complexes

DermatansulfateDermatansulfate

– Chondroitinsulfate B (CSA-B) = dermatansulfate contains iduronic acid instead of GlcUA

– Location: derm, tendons, heart valves, blood vessels.– When there is a deficiency of the lysosomal enzymes, they are

unable to completely decompose the mucopolyglucides, thus the dermatansulfate is accumulated in the tissues, and excreted in the urine (Hurler disease - fatal)

3. Heparin3. Heparin

• Structure:– A complex mixture of linear polysaccharides:– The diglucide units are varied (glucuronic or iduronic sulfated

acid + glucozamine N-sulfated or N-acetylated) linked α-1,4. The degree of sulfation of the saccharide units is varied.

• Location: in the blood, aorta, lungs• Synthesized in the mast cells lining the artery walls in the

liver, skin, lungs• Role:

– has anticoagulant properties and– coenzyme in lipoproteinlipase system from the walls of

capillaries (role in the hydrolysis of triglycerides, VLDL)

NEUTRAL GAGsNEUTRAL GAGsKeratansulfatesKeratansulfates

Formed of acetilated hexozamines, complexed with proteinsFormed of acetilated hexozamines, complexed with proteins

Location: cartilages associated with chondroitinsulfates, skin, Location: cartilages associated with chondroitinsulfates, skin, conective tissueconective tissue

FUNCTIONS OF SULFATED PROTEOGLYCANSFUNCTIONS OF SULFATED PROTEOGLYCANS

Binds waterBinds water – in the tissues exposed to high pressures (joints cartilage, – in the tissues exposed to high pressures (joints cartilage, nucleus pulposus, skin)nucleus pulposus, skin)

Filter Filter – salts and compounds with low molecular mass can diffuse – salts and compounds with low molecular mass can diffuse (basement membranes)(basement membranes)

Ionized at neutral pH – Ionized at neutral pH – cation exchangercation exchanger (Na (Na++ is more concentrated in the is more concentrated in the matrix of cartilage)matrix of cartilage)

Regulating calcification of cartilageRegulating calcification of cartilage, inhibiting the crystallization of calcium , inhibiting the crystallization of calcium phosphatephosphate

Interact with fibrous proteinsInteract with fibrous proteins collagen or elastic, collagen or elastic,

Dermatansulfate, heparansulfate and heparine form insoluble complexes Dermatansulfate, heparansulfate and heparine form insoluble complexes with LDL – involved in with LDL – involved in atherosclerosisatherosclerosis patogenic mechanism patogenic mechanism

Heparin highly negatively charged, cannot coilup and cross-link; stable Heparin highly negatively charged, cannot coilup and cross-link; stable complexes with cationscomplexes with cations

Blood coagulationBlood coagulation

BIOLOGICAL FUNCTIONS OF POLYGLUCIDESBIOLOGICAL FUNCTIONS OF POLYGLUCIDES

EnergeticEnergetic function – glycogen function – glycogen

SupportiveSupportive function – cellulose, chondroitinsulfate in bones function – cellulose, chondroitinsulfate in bones

StructuralStructural function – extracellular material and biological cement – function – extracellular material and biological cement – hyaluronic acidhyaluronic acid

Hydro-osmoticHydro-osmotic and ion-regulating functions – retain water and and ion-regulating functions – retain water and cations, controlling the extracellular osmotic pressurecations, controlling the extracellular osmotic pressure

CofactorCofactor – heparin anticoagulant and antilipemic factor; – heparin anticoagulant and antilipemic factor; dermatansulfate in the aorta acts as anticoagulantdermatansulfate in the aorta acts as anticoagulant