UofT BCH210 Enzymes Summary

HORMONE SIGNALLING PATHWAYS
Enzyme Type of Reaction involved in Activation Inhibition Area in body
enzyme

Creatine kinase Transferase Use of phosphocreatine to Muscles
generate ATP

Glycogen Transferase Glycogenolysis -phosphorylation of Ser14 -dephosphorylation by Muscles + liver
phosphorylase (GP) -generate G1P from -AMP/low energy PP-I
non-reducing ends of (allosteric) -ATP/high energy
glycogen (allosteric)
-G6P (allosteric)

Phosphoglucomutase Isomerase Conversion of G1P into G6P, -phosphorylation of Ser Muscles + liver
or vice versa

G-6-phosphatase Transferase Removal of phosphate from Liver
G6P (hydrolysis) to store
glucose

Protein phosphatase I Transferase Insulin signalling -insulin binding All cells
(PP-I) -inactivates GP, activates GS

UDP-glucose Transferase Conversion of G1P into All cells
pyrophosphorylase UDP-glucose

Glycogen synthase I Addition of glucose (from -dephosphorylation by PP-I -phosphorylation by All cells
(GS) UDP-glucose) onto glycogen -inactivation of GSK3 (via GSK3
insulin binding)
-G6P (allosteric)

, PDC
Enzyme Type of enzyme Reaction involved in Activation Inhibition Area in body

PDC Complex -conversion of pyruvate into -dephosphorylation -phosphorylation
(E1, E2, E3) Acetyl CoA -NADH, Acetyl CoA
Mitochondria
PDC kinase Transferase -turns OFF PDC -NADH, Acetyl CoA -pyruvate, ADP
(allosteric) (allosteric)


PDC phosphatase Transferase -turns ON PDC -Ca2+



CAC
Enzyme Type of enzyme Reaction involved in Activation Inhibition Area in body

Citrate synthase CAC step 1 -ADP, pyruvate -ATP, NADH, citrate Mitochondria
(CS) -formation of citrate from
oxaloacetate + Acetyl CoA

Isocitrate Oxidoreductase CAC step 3 -ADP, Ca2+ -ATP, NADH Mitochondria
dehydrogenase -conversion of isocitrate to
(ICDH) alpha-ketoglutarate
-NADH + CO2

Alpha-ketoglutarate Oxidoreductase CAC step 4 -Ca2+ -ATP, NADH Mitochondria
dehydrogenase -conversion of -succinyl CoA (product
(a-KGDH) alpha-ketoglutarate to inhibition)
succinyl-CoA; NADH + CO2