Metabolism Flashcards
Rate determining enzyme of glycolysis
Phosphofructokinase-1 (PFK-1)
Rate determining enzyme of gluconeogenesis
Fructose-1,6-bisphosphate
Rate determining enzyme of TCA Cycle
Isocitrate dehydrogenase
Rate determining enzyme of glycogenesis
Glycogen synthase
Rate determining enzyme of glycogenolysis
Glycogen phosphorylase
Rate determining enzyme of pentose phosphate pathway
Glucose-6-phosphate dehydrogenase (G6PD)
Rate determining enzyme of de novo pyrimidine synthesis
carbamoyl phosphate synthetase II
Rate determining enzyme of de novo purine synthesis
glutamine-phosphoribosylpyrophosphate (PRPP) amidotransferase
Rate determining enzyme of urea cycle
carbamoyl phosphate synthetase I
Rate determining enzyme of fatty acid synthesis
Acetyl-CoA Carboxylase (ACC)
Rate determining enzyme of fatty acid oxidation
Carnitine acyltransferase I
Rate determining enzyme of ketogenesis
HMG-CoA Synthase
Rate determining enzyme of cholesterol synthesis
HMG-CoA Reductase
What do NADH, NADPH, and FADH2 carry?
electrons
What do CoA and lipoamide carry?
Acyl groups
What does biotin carry?
CO2
What does tetrahydrofolate carry?
1-carbon units
What does S-adenosylmethionine carry?
methyl groups
What does TPP carry?
Aldehydes
NADPH is used in what four things
1) anabolic processes
2) respiratory burst
3) cytochrome p-450 system
4) glutathione reductase
NAD+ is usually used in catabolic or anabolic processes?
Catabolic
Is it glucokinase or hexokinase in the liver?
Glucokinase
What has a lower Km – glucokinase or hexokinase?
hexokinase
What has a lower Vmax – glucokinase or hexokinase?
hexokinase
True or false: hexokinase is induced by insulin?
False. Glucokinase is though
True or false: hexokinase is feedback inhibited by glucose-6-phosphate?
True. Glucokinase is not, however
How many NADH are produced from glycolysis?
two
Enzymes in glycolysis which require ATP input (2)
1) Hexokinase/glucokinase
2) phosphofructokinase-1
Enzymes in glycolysis which produce ATP (2)
1) phosphoglycerate kinase
2) pyruvate kinase
Regulator of hexokinase
Glucose-6-phosphate (negative)
Regulator of glucokinase
Fructose-6-phosphate (negative)
Regulators of phosphofructokinase-1 (4)
1) AMP (pos)
2) fructose-2,6-bisphosphate (pos)
3) ATP (neg)
4) citrate (neg)
Regulators of pyruvate kinase (3)
1) fructose-1,6-bisphosphate (pos)
2) ATP (neg)
3) alanine (neg)
What reverses function between fructosebisphosphatase-2 and phosphofructokinase-2 (same enzyme)?
Phosphorylation by protein kinase A
Five cofactors necessary for pyruvate dehydrogenase’s function
1) Thiamine pyrophosphate
2) lipoic acid
3) CoA
4) FAD
5) NAD+
Causes a buildup of pyruvate that gets shunted to lactate and alanine. X-linked condition
Pyruvate dehydrogenase complex deficiency
Four destinations of pyruvate
1) alanine
2) oxaloacetate
3) TCA cycle
4) lactate
FADH2 produced by the TCA Cycle
1
NADH produced by the TCA cycle
3
CO2 produced by the TCA cycle
2
Five cofactors necessary for alpha-ketoglutarate’s function
1) Thiamine pyrophosphate
2) lipoic acid
3) CoA
4) FAD
5) NAD+
Four irreversible enzymes of gluconeogenesis
1) pyruvate carboxylase
2) Phosphoenolpyruvate carboxykinase
3) fructose-1,6-biphosphatase
4) glucose-6-phosphatase
Where does the pentose phosphate pathway occur in the cell?
cytoplasm
What does pyruvate carboxylase require?
biotin and ATP
Activator of pyruvate carboxylase
Acetyl-CoA
Phosphoenolpyruvate carboxykinase requires ATP or GTP?
GTP
Regulators of fructose-1,6-bisphosphatase (3)
1) Citrate (pos)
2) AMP (neg)
3) fructose-2,6-bisphosphate (neg)
ATP produced by ATP synthase per NADH
2.5 ATP
ATP produced by ATP synthase per FADH2
1.5 ATP
Involves a defect in fructokinase. Autosomal recessive. Benign, asymptomatic condition since fructose is not trapped in cells.
Essential fructosuria
