Glycolysis Enzymes and inhibitors/stimulators Flashcards Preview

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Flashcards in Glycolysis Enzymes and inhibitors/stimulators Deck (53):
1

Hexokinase

-Catalyzes glucose to glucose-6-phosphate
-Stimulated by insulin
-Inhibited by Glucose-6-phosphate

2

Phosphofructokinase 1

-Catalyzes fructose-6-phosphate to fructose 1,6-bisphosphate
-Stimulated by hormones (fructose 2,6-bisphosphate, ADP, AMP)
-Inhibited by ATP, citrate

3

Pyruvate Kinase

-Catalyzes PEP to pyruvate (glycolysis)
-Stimulated by fructose 1,6-bisphosphate, insulin
-Inhibited by ATP

4

Pyruvate Carboxylase

-Pyruvate to OAA (done if acetyl CoA is high, and there i no need for more ---convert to OAA so there is more to react with)
-stimulated by Acetyl CoA
-inhibited by insulin

5

PEP carboxykinase

-OXA to phophoenolpyruvate (gluconeogenesis)

-inhibited by insulin, AMP
-stimulated by Glucagon

6

Fructose 1,6-bisphosphatase

-Fructose1.6-bisphosphate to Fructose 6-phosphate (gluconeogenesis)

-Inhibited by Fructose 2,6, bisphosphate, AMP
-Stimulated be citrate

7

Glucose 6-phosphatase

G6P to glucose
Inhibited by insulin
Stimulated by Glucagon, epi

8

Glucose 6-phosphate dehydrogenase

G6P to phosphogluconolactone
-Inhibited by NADPH

9

Glucokinase

-Glucose to G6P (in glycogen breakdown) (hexokinase isozyme in the liver)
-NOT inhibited by G6P
-Stimulated by insulin

10

Phosphogulcomutase

G6P to G1P (part of glycogen breakdown)

11

UDP-glucosepyrophosphorylase

Glucose 1-P UTP to UDP (part of the glycogen breakdown pathway

12

Glycogen Synthase

Adds glucose to glycogen
-Inhibited by glucagon, epi
-Stimulated by insulin

13

Glycogen phosphorylase

Releases G1P units from glycogen
-Inhibited by insulin
-Stimulated by glucagon, epi

14

Debranching enzyme (just what is it)

Part of the glycogen breakdown

15

Branching enzyme (just what is it)

Part of the glycogen synthesis reactions

16

What is the equivalent enzymes for Hexokinase in glyconeogeneis?

Glucose-6-phosphatase

17

What is the equivalent enzymes for phosphofructokinase in glyconeogeneis?

Fructose 1,6 bisphophatase

18

What is the equivalent enzymes for Pyruvate kinase in glyconeogeneis?

There are two:
-PEP carboxylase
-Pyruvate carboxylase

Note that PEP carboxylase acts on OAO.

19

Phosphoglucomutase

Catalyzes reaction from G1P to G6P and vice versa. Used in the formation/breakdown of glycogen.

20

Type I GSD

Defect in the G6Pase--liver cannot export glucose, and thus builds up. Leads to hypoglycemia and increased liver stores

21

Type II GSD

Also known as Pomp disease
-Deficiency in acid maltase (alpha-gluconsidase). This enzyme is required for degradtaion of glycogen that slowly accumulates in the lysosome. Thus over time, the lysosome fills with glycogen and kills the cell. Death occurs by cardiac or respiratory failure.

22

Type III GSD

Cori disease
-A defect in glycogen debranching enzyme, causing glycogen granules to grow large because only the non-branched chain can be degraded.

23

Type V GSD

Also known as McArdle disease
-Defect in muscle glycogen phosphorylase, which renders the muscles unable to utilize stored glycogen.
Lead to exertional muscle weakness.

24

Na+/Glucose transporters: where are they found, what to the transport?

Found in the small intestine
Active transport of glucose, galactose from intestinal cell wall into the epithelial cells.

25

GLUT 1: where are they found, what do they transport?

All tissues
basal glucose/galactose uptake

26

GLUT 2: where are they found, what do theytransport?

Liver, intestines, and beta cells of the pancreas
Liver removes glucose/galgactose from blood
Intestine:release of glucose/galactose from epithelial cells into the circulation
Pancrease- regulation of insulin uptake

27

GLUT 3: where are they found, what do they transport?

All tissues
basal glucose/galactose uptake

28

GLUT 4: where are they found, what do they transport?

Muscle and adipose tissues
induced by insulin to take up glucose/galactose

29

GLUT 5: where are they found, what do they transport?

Small intestine, liver, others
Uptake fructose

30

What is Hunter disease? What is the defective enzyme, substrate built up, and inheritance pattern?

MR, skeletal abnormalities
Due to defective iduronate sulfatase
Builds up dermatan sulfate and heparan sulfate
XR

31

What is Hurler's disease? What is the defective enzyme, substrate built up, and inheritance pattern?

Mr, Skeletal abnormalities
Due to defective alpha iduronase
Builds up dematan sulfate and heparan sulfate
AR

32

What is Sanflippo's disease? What is the defective enzyme, substrate built up, and inheritance pattern?

MR, with slight physical abnormalities
Due to defective A, B, C, D root in different defects of heparan sulfate degradation
Builds up heparan sulfate
AR

33

PDH protein kinase

Inhibits the PDH cycle via phosphorylation
Activated by acetyl-CoA, NADH (increases PDH complex)
Inhibited by NAD, CoASH, and ADP

34

Citrate can be diverted from the CAC to produce what?

Acetyl -CoA to go to FA/sterol synthesis

35

Alpha ketoglutarate can be diverted from the CAC to produce what?

Glutamate to yield amino acids/purines

36

Succinyl-CoA can be diverted from the CAC to produce what?

Porphyrins (hemes/cytochromes)

37

Malate can be diverted from the CAC to produce what?

Pyruvate to produce alanine

38

OAO can be diverted from the CAC to produce what?

Phosphoenol-pyruvate to glucose OR
Aspartate to produce other amino acids.

39

Alpha keto glutarate dehydrogenase complex

Involved in the CAC
Inhibited by NADH and succinyl CoA

40

Isocitrate dehydrogenase

Involved in the CAC
Stimulated by ADP
Inhibited by NADH

41

What is the name of complex 1 in the ETC (named by the reaction it does)?

NADH-CoQ reductase

42

What is the name of complex 2 in the ETC (named by the reaction it does)?

Succinate CoQ reductase

43

What is the name of complex 3 in the ETC (named by the reaction it does)?

CoQH2 - Cytochrome C reductase

44

What is the name of complex 4 in the ETC (named by the reaction it does)?

Cytochrome Oxidase

45

What is the effect of Atractyloside?

Inhibits adenine nucloetide translocase

46

Fructosemia (not fructose urea) is a problem with what enzyme? What are the symptoms?

Aldolase B
Heptapmegally, liver failure, jaundice, inability to utilize glycogen

47

Galactosemia is a problem with what enzyme? What are the symptoms?

Galactokinase, UDP galactose uridyl transferase, or UDPG epimerse
Symptoms include MR, liver failure

48

What is protein phosphatase 1 (PP1)? How is it activated?

An enzyme in the liver, activated by insulin, that dephosphorylates proteins phosphorylated by PKA. (reverses glucagon effects)

49

Does insulin increase or decrease the liver's uptake of glucose?

Neither, it always wants glucose

50

How does glucagon affect muscle cell glycolysis?

It doesn't. There is no glucagon receptor.

51

Glucose-6-phosphate deficiency affects which metabolic pathway? Symptoms?

PPP
Hemolytic anemia due to inability to produce glutathione

52

For Tay-Sach's disease, what is:
1. the defective enzyme
2. Accumulated lipid
3. Presentation

1. beta-hexosaminidase
2. Ganglioside
3. MR, blindness, death before 3 y.o.

53

For Gaucher's disease, what is:
1. the defective enzyme
2. Accumulated lipid
3. Presentation

1. Beta-glucoside (cerebrosidase)
2. Glucocerebroside
3. Long bone defects, hepatosplenomegaly