Influence of glycerol on the activity and tetramer-dimer state of lactate dehydrogenase isozymes.
1. The effects of glycerol on H4 and M4 isozymes of LDH were studied at 5 degrees C. 2. For H4-LDH, glycerol at 1 or 3% progressively shifted the pyruvate concentration that produced optimal activity to a lower value; glycerol at 1% also markedly increased enzyme relative activity at low enzyme concentration. 3. Correlated with this was a parallel change in H4-LDH dissociation-association as glycerol increased with maximal content of the active dimer found always at the pyruvate concentration producing maximal enzyme activity, and a progressive decrease in dimer content at concentrations of pyruvate that produced substrate inhibition. 4. These experiments confirm the functional importance of dimer-tetramer interconversions in promoting the pyruvate-reducing vs lactate-oxidizing activities of LDH. 5. Glycerol also enhanced enzyme ternary complex formation, elution of H4-LDH from AMP-Sepharose by low concentrations of ADP-ribose increasing in the presence of 1 or 3% glycerol.
Yamamoto
S
S
Radioisotope Center, Nagoya University, Japan.
Storey
K B
KB
D000818:Animals; D002417:Cattle; D004789:Enzyme Activation / Q000187:drug effects; D005990:Glycerol / Q000494:pharmacology*; D007527:Isoenzymes / Q000378:metabolism*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D007773:Lactates / Q000494:pharmacology; D009132:Muscles / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D010084:Oxidation-Reduction / Q000187:drug effects; D011773:Pyruvates / Q000494:pharmacology; D011817:Rabbits; D013696:Temperature
D007527:Isoenzymes; D007773:Lactates; D011773:Pyruvates; D007770:L-Lactate Dehydrogenase; D005990:Glycerol