BioChem Master topics

PFK

glycolysis committed step (F6P → F1,6-BP

Pyruvate kinases

glycolysis final step (PEP → pyruvate)

PDH complex

pyruvate → acetyl-CoA

CA cycle

oxidative decarboxylations

acetyl-CoA carboxylase

fatty acid synthesis committed step (acetyl-CoA → malonyl-CoA)

Acetyl-CoA carboxylase

anabolic (on when energy and building blocks are abundant, off when energy is low)

Catabolic enzymes

high ATP → inhibits, High AMP → activates

Anabolic enzymes

High ATP → activates, High AMP → inhibits

PFK

High ATP/citrate → inhibits, High AMP/F2-6BP→ activates

PFK two binding sites

active site - high affinity(low atp levels), allosteric - low affinity(high atp levels)

F2-6BP

pure signal, no metabolic role. Set by insulin/glucagon

Citrate effect on PFK vs Acetyl-CoA carboxylase

opposite affects, inhibits pfk and activates acetyl-coa

PDH complex

Activated by low energy (high atp, low adp) and pyruvate. Inhibited by ATP and acetyl-coA and NADH

Pyruvate Kinase (glycolysis step 10)

inhibited by ATP. Activated by F1-6BP.

feed-forward activation

upstream substrate or product activating a downstream enzyme. (1) f1-6bp activates pyruvate kinase (2) pyruvate activates PDH

CA Cycle

Activates from low energy (high adp/amp) inhibits from high atp and high nadh and succinyl-coA.

Acetyl-CoA Carboxylase

Activates from ATP , citrate , insulin. Inhibitors are AMP, palmitoyl-CoA (fatty acid abundance/ product) and catabolic hormones glucagon & epinephrine

high NADH inhibits catabolic pathways

shows the ETC is backed up, so point in making more reduced carriers so slows catabolism down

Glucagon & epinephrine

catabolism

Insulin

anabolism