Title: Chemistry 501 Handout 14 Glycolysis, Gluconeogenesis, and
1Chemistry 501 Handout 14 Glycolysis,
Gluconeogenesis, and the Pentose Phosphate
PathwayChapter 14
Lehninger. Principles of Biochemistry. by Nelson
and Cox, 5th Edition W.H. Freeman and Company
2Major pathways of glucose utilization
3The first phase of glycolysis (the preparatory
phase)
4The second phase of glycolysis (the payoff phase)
O
5The two phases of glycolysis
6Three possible catabolic fates of the pyruvate
formed in glycolysis
71. Phosphorylation of glucose
82. Conversion of glucose 6-phosphate to fructose
6-phosphate
9The phosphohexose isomerase reaction
anomeric carbon
103. Phosphorylation of fructose 6-phosphate to
fructose 1,6-bisphosphate
114. Cleavage of fructose 1,6-bisphosphate
12The class I aldolase reaction
imine
135. Interconversion of the triose phosphates
Fate of the glucose carbons in the formation of
glyceraldehyde 3-phosphate
146. Oxidation of glyceraldehyde 3-phosphate to
1,3-bisphosphoglycerate
15The glyceraldehyde 3-phosphate dehydrogenase
reaction
167. Phosphoryl transfer from 1,3-bisphosphoglycera
te to ADP
178. Conversion of 3-phosphoglycerate to
2-phosphoglycerate
18The phosphoglycerate mutase reaction
199. Dehydration of 2-phosphoglycerate to
phosphoenolpyruvate
2010. Transfer of the phosphoryl group from
phosphoenolpyruvate to ADP
21Entry of glycogen, starch, disaccharides, and
hexoses into the preparatory stage of glycolysis
Feeder pathways for glycolysis
22Feeder pathways for glycolysis
23Dietary polysaccharides and disaccharides undergo
hydrolysis to monosaccharides
24Glycogen breakdown by glycogen phosphorylase
25Other monosaccharides enter the glycolytic
pathway at several points
26Conversion of galactose to glucose 1-phosphate
Defects in any of the three enzymes in this
phatway Cause galactosemia in humans
Galactose methabolite involved in
galactokinase-deficiency galactosemia
27Fates of pyruvate under anaerobic conditions
Fermentation
Pyruvate is the terminal electron acceptor in
lactic acid fermentation
no net change in NAD or NADH
acidification in muscle and blood limits
the period of vigorous activity
28Ethanol is the reduced product in ethanol
fermentation
tightly bound coenzyme, thiamine pyrophosphate
Industrial-scale fermentations yield a variety of
common foods and industrial chemicals
29The alcohol dehydrogenase reaction
30Thiamine pyrophosphate (TPP) and its role in
pyruvate decarboxylation
31Thiamine pyrophosphate
32Gluconeogenesis
Carbohydrate synthesis from simple precursors
33Opposing pathways of glycolysis and
gluconeogenesis in rat liver
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35Synthesis of phosphoenolpyruvate from pyruvate
36Role of biotin in the pyruvate carboxylase
reaction
37Alternative paths from pyruvate to
phosphoenolpyruvate
38Citric acid intermediates and many amino acids
are glucogenic
Citrate Isocitrate a-ketoglutarate Succinyl-CoA Su
ccinate Fumarate Malate
Pyruvate
oxaloacetate
C.A.C.
Amino acid catabolism
C.A.C. Intermediates
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43Feeder pathways for glycolysis (preparatory phase)
44General scheme of the pentose phosphate pathway
of glucose oxidation
45Oxidative reactions of the pentose phosphate
pathway
NADP
46Nonoxidative reactions of the pentose phosphate
pathway
The nonoxidative phase recycles pentose
phosphates to glucose 6-phosphate
47The first reaction catalyzed by transketolase
thiamine pyrophosphate
General reaction Transfer of a two-carbon group
from a ketose donor to an aldose acceptor
48The reaction catalyzed by transaldolase
The second reaction catalyzed by transketolase
49Role of NADPH in regulating the partitioning of
glucose 6-phosphate between glycolysis and the
pentose phosphate pathway
50Role of NADPH and glutathione (GSH) in protecting
cells against highly reactive oxygen derivatives