TOT enzymatic activity for glycolysis, PDH cmplx, CAC

isocitrate DH (E. coli)

KINASE: inhibited by C3PPO

PHOSPHATASE: stimulated by C3PPO

C3PPO mnemonic

allosteric factors affecting isocitrate DH phosphokinases

C: isocitrate
3: 3PG (3-phosphoenolpyruvate)
P: PEP (phosphoenolpyruvate)
P: PyR (pyruvate)
O: oxaloacetate

a-ketoglutarate DH

inhibited by ATP, succinyl CoA, NADH

citrate synthase

inhibited by ATP

glycolysis in skeletal muscle

only irreversible enzymes are regulated: hexokinase, PFK, pyruvate kinase

F-1,6-bisphosphatase (liver)

stimulates: citrate

glucokinase (liver only)

inhibited: F6P

hexokinase (muscle only)

G6P inhibits

PFK-1 (muscle OR liver)

stimulated: AMP (low ATP/AMP ratio), F-2,6-bP

inhibited: citrate, low pH, high ATP

PFK-2 KINASE (liver)

unphosphorylated: kinase STIMULATED

• stimulated: Pi (indicates lots of ADP/no ATP)

• inhibited: citrate

PFK-2 PHOSPHATASE (liver)

when phosphorylated: phosphatase STIMULATED

• inhibited: F6P

• stimulated: glucagon

pyruvate kinase (muscle OR liver)

stimulated: F-1,6-bP

inhibited: high ATP, alanine, glucagon

phosphorylated: INCREASED activity

pyruvate carboxylase (gluconeogenesis)

stimulated: acetyl CoA

E2 (PDH cmplx)

stimulated: CoA(-SH)

inhibited: acetyl CoA

“co- prefix: 2 existing → CoA

E3 (PDH)

stimulated: NAD+

inhibited: NADH

3 → NAD (rhyme)

citrate synthase

inhibited: ATP

isocitrate DH (mammals)

stimulated: ADP, NAD+, Ca2+

inhibited: ATP, NADH

a-ketoglutarate DH

inhibited: ATP, NADH, succinyl CoA

fructose-1,6-bisphosphatase

stimulated: citrate

pyruvate DH

KINASE

stimulated: acetyl CoA, NADH
inhibited:

PHOSPHATASE

stimulated: high Ca2+