CARBOHYDRATE CHEMISTRY 1. STEREOISOMERS - Cpds. with the same formula and attachment of atoms but with different arrangements of the atoms in space. 2. ENANTIOMERS Stereoisomers in which one isomer is the non-superimposable mirror image of the other. o Configuration is determined by: position of the OH on the highest number asymmetric carbon Least oxidized carbon: a Carbon linked to four different atoms farthest from the carbonyl carbon o L configuration: if OH on Left o D configuration: if OH on Right; cells prefer this configuration 3. CHIRALITY- The C molecule has 4 different substrates attached to it -TETRAHEDRAL CARBON/CHIRAL CENTER - They are NON SUPERIMPOSABLE - GLYCERALDEHYDE: most studied carbon 4. CARBONYL CARBON - A carbon that is double bonded with O2 in a fischer/open formula - Most oxidized carbon 5. EPIMER- Stereoismers which differ in the arrangement of substituents in ONLY ONE POSITION. Epimerase enzyme responsible for interconversion of epimers - In monosaccharide epimers, the position of OH distinguishes the monosaccharide. The carboxyl group remains the same.

D-Glucose and D-Mannose epimers at C2

FISCHER PROJECTION FORMULA

HAWORTH FORMULA

Linear formula which can be depicted in the D- or L-form

The cyclic form of the Fischer formula that can be depicted in the or form.

Counting of Carbons starts from the topmost carbon going down. The topmost carbon is thus labeled Carbon 1 or C1 or Position 1

Locate the oxygen in the ring. The Carbon on either side of the oxygen. The carbon with the attached OH group is the Anomeric Carbon

OH on RIGHT : DEXTER OH on LEFT: LEVO

: OH group is axial DOWN : OH group is axial UP

Furanose 5 membered ring (Fructose) Pyranose 6-membered ring (Glucose)

MOST STABLE ANOMERS isomeric forms of monosaccharides that differ only about the hemiacetal/hemiketal C.

ALDEHYDE KETONES

Molecule wherein the carbonyl carbon number 1 binds with oxygen

Molecule wherein the carbonyl carbon number 2 binds with oxygen

R Group is a HYDROGEN atom

R Group is another HYDROXYMETHYL group When Aldehyde group tautomerizes into a keto group

React with an alcohol to form a HEMIACETAL

React with an alcohol to form a HEMIKETAL

BIOLOGICALLY IMPORTANT CARBOHYDRATES: MONOSACCHARIDES simple sugars; ALL ARE REDUCING SUGARS Carbohydrates that cannot be hydrolyzed into simpler compounds

GLUCOSE GALACTOSE MANNOSE FRUCTOSE RIBOSE DEOXYRIBOSE ALDOHEXOSE - Monosaccharide that has both analdehyde (aldose) and six carbons (hexose) Pyran-D is the most stable form of glucose

Ketopentose (5 - Carbon ring)

Aldopentose

Empirical formula (C6-H12-O6) Chief source of energy for living organisms Most important Monosaccharide. Sugar of the body. Occurs naturally in the D-configuration vs. L-configuration

Differs with Glucose in the position of OH at C4 (Non-reducing end) Can be changed to glucose in the liver and metabolized. - Synthesized in the mammary glands to make the lactose of milk. Less soluble and less sweet compared to glucose - A constituent of glycolipids and glycoproteins.

Differs with Glucose in the OH configuration at C2. - A constituent of many glycoproteins

Isomer of 3 aldohexose Differs in Glucose in C1 and C2 Can be changed to GLUCOSE in the liver Furan Ring -C1 and C6 are outside the ring and susceptible to nucleophilic attack.

Structural elements of nucleic acids and coenzymes, e.g. ATP, NAD, NADP, Flavoproteins. RNA DNA

Intermediates in the HMP Shunt.

C2 in ribose is OH

In deoxyribose, C2 reduced to H

BIOLOGICALLY IMPORTANT CARBOHYDRATES: DISACCHARIDES formed when anomeric carbon of a sugar molecule interacts with one of several hydroxyl groups in other sugar molecules

Bonded by glycosidic bonds: GLYCOSIDIC BOND FORMATION Covalent bond join a CHO molecule (Anomeric C of 1st molecule and C4 of 2nd molecule) MALTOSE ISOMALTOSE LACTOSE SUCROSE 1,4 glycosidic bond linkage 1,6 glycosidic bond linkage 1,4 glycosidic bond linkage 1- 2 glycosidic bond linkage -D-glucose + -D-glucose -D-glucose + -D-glucose -D-galactose +-D-glucose -D-glucose + -D-fructose broken down by MALTASE broken down by

SUCRASE-ISOMALTASE COMPLEX broken down by LACTASE, -GALACTOSIDASE

broken down by SUCRASE

linear branched Lactose intolerance indigestion of lactose-richfoods caused by depletion of enzymes lactase or - galactosidase

*synthesized only in plants *commonly known as table sugar

Reducing sugar Non-reducing sugar

BIOLOGICALLY IMPORTANT CARBOHYDRATES: POLYSACCHARIDES - long polymers of oligosaccharides formed via glycosidic linkages, which could either be linear or highly branched, by multiple monosaccharides

- OLIGOSACCHARIDES: contain 3-4 monosaccharide connected through glycosidic bonds - Functions: o Energy storage (Amylose, Glycogen) o Structural integrity maintenance (Cellulose) - Types of Polysaccharides: o Homoglycan/homopolymer/homopoly saccharide a long polymer of one type of monosaccharide, such as Starch o Heteroglycan/heteropolymer/heteropo lysaccharide a long polymer consisting of more than one type of monosaccharide STARCH CELLULOSE GLYCOGEN a long polymer of glucose synthesized by plants for energy storage, found in potatoes, legumes, and other vegetables

A long polymer of glucose with - 1,4 linkages synthesized by plants to serve a structural role; found in the cell wall of plants

a long polymer of glucose with one -1,6 linkage for 8-12 -1,4 linkages synthesized by animal cells for energy storage

Its digestion begins in the mouth through - amylase, which produces an intermediate called -dextrins, an oligosaccharide containing -1,6 glycosidic bonds and -1,4 glycosidic bonds.

Its linkage makes it insoluble since no enzyme in the human body is able to break glycosidic bonds.

Highly branched and compac than amylopectin.

Two main constituents of starch: o Amylose an unbranched (linear) chain of glucose residues connected by -1,4 linkages. Involved in glucose storage in plants.

o Amylopectin - branched version of amylose containing both an -1,4 linkages and -1,6 linkages, which allows for branching. - Both constituents are rapidly hydrolyzed by salivary and pancreatic -amylase