Oxidoreductases and Oxygenases

Abstract

Oxidoreductases (dehydrogenases or oxidases) catalyze the addition or the removal of hydrogen or electrons. Oxygenases bring ahout the incorporation of oxygen which originates from molecular oxygen. C 2.1 Dehydrogenases Containing Pyridine Nucleotides C 2.1.1 Mechanism of Reaction In a large numher of dehydrogenations the hydrogen of the suhstrate is transferred to the pyridine nucleotides NAD+ and NADP+ (D 16.2) according to the following equation: H ~CONH 2 ltJ + N I R Table 14. Stereospecificity of dehydrogenases with respect to position 4 of the pyridine nucleus of NAD+ and NADP+ Transfer of hydrogen from Alcohol dehydrogenase (alcohol: NAD+ oxidoreductase, D 2) Hydroxymethylglutaryl CoA reductase (mevalonate: NADP+ oxido-reductase, D 6) Shikimate dehydrogenase (shikimate: NADP+ oxidoreductase, D 8) Cyclopeptine dehydrogenase (cyclopeptine: NAD(P)+ oxidoreductase, D 8.4.2) Histidinol dehydrogenase (L-histidinol: NAD+ oxidoreductase, D 20) Glucose-6-phosphate dehydrogenase (o-glucose-6-phosphate: NADP+ oxidoreductase, D 1. 2) y-Coniceine reductase (D 3.3.1) Squalene synthase (D 6) Glutamate dehydrogenase (L-glutamate: NAD + oxidoreductase, c 2.1.2) ß-Hydroxysteroid dehydrogenase (3 [or 17] ß-hydroxysteroid: NAD(P)+ oxidoreductase, D 6.4.6) M. Luckner, Secondary Metabolism in Microorganisms, Plants and Animals