Enzymes of glyolysis and gluconeogenesis

Question 1

What are the five types of enzymatic reactions in glycolysis?

Answer 1

Phosphorylation, phosphoryl shift, isomerisation, dehydration, redox

Question 2

What types of enzymes phosphorylate?

Answer 2

Kinases

Question 3

What types of enzymes shift phosphoyl?

Answer 3

Mutases (Pi remains within molecule but shifts from one O to another O)

Question 4

What types of enzymes isomerise?

Answer 4

Isomerases

Question 5

What general isomerisation reactions happen in glycolysis?

Answer 5

Aldose ketose

Question 6

What types of enzymes dehydrate?

Answer 6

Dehydratases

Question 7

What types of enzymes redox?

Answer 7

Dehydrogenases

Question 8

What are the ten enzymes involved in glycolysis (in order of reactions)?

Answer 8

Hexokinase/glucokinase; phosphoglucoisomerase; phosphofructokinase; fructose disphosphate aldolase; triose phosphate isomerase; GALP dehydrogenase; phosphoglycerate kinase; phosphorylglycerate mutase; enolase; pyruvate kinase

Question 9

What does hexokinase/glucokinase do?

Answer 9

Glucose –> glucose-6-p; requires Mg2+

Question 10

What does phosphoglucoisomerase do?

Answer 10

Glucose-6-p –> fructose-6-p; carbonyl oxygen shifted from C1 to C2; aldose –> ketose

Question 11

What does phosphofructokinase do?

Answer 11

Fructose-6-p –> fructose-1,6-bisp; requires Mg2+

Question 12

What does fructose disphosphate aldolase do?

Answer 12

Fructose-1,6-bisp –> GALP + DHA-P; aldol cleavage

Question 13

What does triose phosphate isomerase do?

Answer 13

DHA-P –> GALP; ketose –> aldose

Question 14

What does glyceraldehyde-3-phosphate dehydrogenase do?

Answer 14

GALP –> glycerate-1,3-bisphosphate

Question 15

What does phosphoglycerate kinase do?

Answer 15

ADP + Pi –> ATP

Question 16

What does phosphorylglycerate mutase do?

Answer 16

Glycerate-3-phosphate –> glycerate-2-phosphate

Question 17

What does enolase do?

Answer 17

Glycerate-2-phosphate –> phosphorenolpyruvate

Question 18

What does pyruvate kinase do

Answer 18

ADP + Pi –> ATP

Question 19

What is gluconeogenesis?

Answer 19

Formation of glucose from non-carb sources

Question 20

What compounds may enable gluconeogenesis?

Answer 20

Lactate, glutamate, alanine

Question 21

Where does gluconeogenesis occur?

Answer 21

Primarily in liver

Question 22

What is the purpose of gluconeogenesis?

Answer 22

Maintain blood glucose concentration during fasting and starvation

Question 23

How is lactate converted to glucose?

Answer 23

Lactate shuffled to liver. Lactate –> pyruvate; pyruvate –> oxaloacetate (pyruvate carboxylase); oxaloacetate –> phosphophenolpyruvate (phosphophenolpyruvate carboxylase); phosphophenolpyruvate –> F-1,6,BP; F-1,6-BP –> F-1-P (fructose-1,6-phosphatase); F-1P –> glucose

Question 24

How is fructose-1,6-phosphatase regulated?

Answer 24

AMP inhibits action of fructose-1,6-phosphatase and stimulates phosphofructokinase (opposing enzyme); ATP stimulates action of fructose-1,6-phosphatase and inhibits phosphofructokinase (opposing enzyme)

Question 25

What basic chemicals are needed for gluconeogenesis?

Answer 25

Oxygen and ATP