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Flashcards in Glycolysis Deck (12):
1

rate-limiting enzyme in glycolysis

Phosphofructokinase-1

2

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

1. AMP
2. fructose 2,6 bisphosphonate

3

2 things that inhibit PFK-1

1. ATP
2. Citrate

4

beginning enzyme in glcolysis (depending on tissue)

hexokinase or glucokinase

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

5

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

6

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

Pyruvate kinase

7

what induces pyruvate kinase activity

1. fructose 1,6 bisphosphonate

8

what two things decrease pyruvate kinase activity

1. ATP
2. Alanine

9

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

10

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)

11

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

12

MCC of glycolytic enzyme deficiency

pyruvate kinase deficiency

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