Lipoyl dehydrogenase from Saccharomyces cerevisiae II. Kinetic and inhibitor studies

Abstract

Kinetic and inhibitor studies have been carried out on lipoyl dehydrogenase (NADH:lipoamide oxidoreductase, EC 1.6.4.3) from Saccharomyces cerevisiae. The results obtained are similar in many respects to those reported for the enzyme prepared from pig heart although some differences have been observed. The overall picture of activity with various electron donors and acceptors is qualitively the same with the two enzymes, the yeast enzyme showing considerably greater activity using K₃Fe(CN)₆ and oxidized 3-acetylpyridine-adenine dinucleotide as electron acceptors. Inhibition of the enzyme by arsenite and copper ions is less marked than that of pig-heart lipoyl dehydrogenase, though again the results are qualitively very similar.