carbohydrate metabolism: mono/disaccharide metabolism
DESCRIPTION
INTER 111: Graduate Biochemistry. Carbohydrate Metabolism: Mono/disaccharide Metabolism. Monosaccharide & Disaccharide Metabolism. Glycogen . R5P. Disaccharides. Glucose. fructose galactose. NADH + H + and ATP. Pyruvate. O 2. H 2 O. aerobic conditions. NADH + H + and FADH 2 - PowerPoint PPT PresentationTRANSCRIPT
Carbohydrate Metabolism:Mono/disaccharide Metabolism
INTER 111: Graduate Biochemistry
Monosaccharide & Disaccharide Metabolism
Electron transportOxidative phosphorylation
R5P Glucose
Pyruvate
NADH + H+
andATP
Glycogen
Disaccharides
Acetyl CoANADH + H+
and FADH2
and CO2
aerobicconditions
citricacidcycle
O2 H2O
ATPADP + Pi
fructosegalactose
Artificial sweeteners
Sugar substitute: food additive to duplicate sugar taste but with less food energy
Sweetness of compounds many fold greater than glucose or sucrose
Ongoing controversy over health risks
Artificial sweeteners
Saccharin – discovered in 1879– 300X sweeter than sucrose– no food energy
Aspartame– Discovered in 1965– 180X sweeter than sucrose aspartame
saccharin
Fructose metabolism
Typical Western diet contains 50 g fructose/day
Fructose found in corn syrup, fruits, and honey
Insulin-independent
SUCROSE
Phosphorylated products of fructose and their
cleavage
Either hexokinase or fructokinase can covalently modify fructose.
Hexokinase phosphorylates glucose rather than fructose, unless [fructose] is unusually high.
Fructokinase found in particular tissues
Fruc
tose
met
abol
ism
Glycolysis
Phosphorylated products of fructose
Fruc
tose
met
abol
ism
Glycolysis
Sorbital metabolism
Lens, kidney, nerve Seminal vesicles
Lactose Synthesis
Occurs in ER and Golgi bodies of human mammary glands
Lactose synthase
Stimulated by prolactin
Galactose metabolism
Galactose metabolism
Galactose metabolic disorders
Classic galactosemia
Uridyltransferase deficiencyAutosomal recessive disorder (1 in 23,000 births)