Coenzyme activity of NAD analogs for 3-isopropylmalate dehydrogenase from thermus thermophilus HB8

Abstract

In order to elucidate the enzyme-substrate-cofactor interaction in 3-isopropylmalate dehydrogenase, the coenzyme activity of NAD analogs which have a 3-substituted pyridine ring was examined. Analogs 3-5 showed diminished kcat values compared with those of NAD+, whereas thiocarboxamide 2 was almost as equally active as NAD+. This suggests that the NH2 functionality of NAD+ is more important for the catalysis of IPMDH than a carbonyl group. © 1999, Taylor & Francis Group, LLC. All rights reserved.