Regulation of Glucose Metabolism

Question 1

selfish organs

Answer 1

brain

muscle

gather glucose from blood

use immediately (only glycolysis) or store

Question 2

regulatory organs

Answer 2

maintain constant [glucose]

remove glucose from blood if [ ] is high

synthesize glucose when [ ] is low, excrete into blood

liver and kidneys

Question 3

which enzymes are allosteric?

Answer 3

large negative delta G (1, 3, 7, 10)

Question 4

overall signal?

Answer 4

need energy (high ADP, AMP) increases flux to make ATP

ample energy (high ATP, fatty acids) decrease flux

Question 5

what activates or inhibits (selfish tissues)

Answer 5

G-6-P buildup inhibits hexokinase

AMP/ADP activates PFK-1; ATP inhibits

ATP, FA, CoA inhibit pyruvate kinase

Question 6

coordinate regulation

Answer 6

difference between selfish and regulatory organs

hexokinase (muscle) always converts G –> G-6-P

glucokinase (liver) only converts G –> G-6-P when G is abundant

Question 7

what activates or inhibits in regulatory organs

Answer 7

glucose buildup activates glucokinase; F-6-P inhibits

F 2,6 bis-P buildup activates PFK-1

F 1,6 bis-P activates pyruvate kinase; ATP, FA, CoA inhibits

new compound to worry about: F 2,6 bis-P

Question 8

F 2,6 bis-P regulatory organs regulation

Answer 8

F 2,6 bis-P buildup inhibits F 1,6 bis-Pase

PFK-2 makes F 2,6 bis-P

to avoid futile cycle must carefully regulate F 2,6 bis-P