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Flashcards in Glycolysis Deck (12)
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rate-limiting enzyme in glycolysis



2 things that increae activity of phosphofructokinase-1 (PFK-1)

1. AMP
2. fructose 2,6 bisphosphonate


2 things that inhibit PFK-1

1. ATP
2. Citrate


beginning enzyme in glcolysis (depending on tissue)

hexokinase or glucokinase

*glucokinase in liver and beta cells of pancreas; hexokinase everywhere else


differences between hexokinase and glucokinase

1. glucokinase--> has a low affinity (high Km), is induced by insulin, and a very high Vmax; ensures liver and pancreas B cells only take up glucose when it is plentiful
2. hexokinase--> high affinity (low Km), low Vmax, and NOT induced by insulin


catalyzes phosphoenol pyruvate--> pyruvate; last step in glycolysis

Pyruvate kinase


what induces pyruvate kinase activity

1. fructose 1,6 bisphosphonate


what two things decrease pyruvate kinase activity

1. ATP
2. Alanine


increased glucagon in fasting state does what to decrease glycolysis and increase gluconeogenesis

glucagon--> activates PKA--> phosphorylates fructose bisphosphatase-2/ phosphofructokinase-2 complex--> activates FBP-2 to convert Fructose 2,6 bisphosphate to fructose 6 phosphate = used in gluconeogenesis


increased insulin during fed state does what to decrease gluconeogenesis and increase glycolysis

insulin--> decreases cAMP and thus PKA activity--> unphosphorylated FBP-2/ PFK-2 complex means more active PFK-2--> converts fructose-6-phosphate to fructose 2,6 phosphate, which increaes activity of Phoshofructokinase-1 = increased glycolysis (PFK-1 converts fructose 6 phosphate to fructose 1,6 bisphosphate, remember PFK-1 is rate-limiting enzyme in glycolysis)


what is the clinical consequence of a glycolytic enzyme deficiency?

hemolytic anemia--> RBC only can use glycolysis, so when its gone, cant make ATP, so Na/K pumps fail, cell swells and lyses


MCC of glycolytic enzyme deficiency

pyruvate kinase deficiency

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