D-α-Hydroxyglutarate Dehydrogenase of Rhodospirillum rubrum

• Published in: Journal of biochemistry (Tokyo) 1975-12, Vol.78 (6), p.1321-1329
• Main Authors: EBISUNO, Toichi, SHIGESADA, Katsuya, KATSUKI, Hirohiko
• Format: Article
• Language: English
• Subjects: Alcohol Oxidoreductases - isolation & purification; Alcohol Oxidoreductases - metabolism; Anaerobiosis; Cytochrome c Group - metabolism; Electron Transport; Glutarates; Hydrogen-Ion Concentration; Kinetics; Mathematics; Rhodospirillum rubrum - enzymology; Structure-Activity Relationship
• ISSN: 0021-924X; 1756-2651
• DOI: 10.1093/oxfordjournals.jbchem.a131030

D-α-Hydroxyglutarate dehydrogenase of R. rubrum grown anaerobically in the light was partially purified and some properties were investigated. 1. The enzyme catalyzes stoichiometrically the dehydrogenation reaction of D-α-hydroxyglutarate into α-oxoglutarate, coupled with the reduction of 2, 6-dichloro-phenolindophenol. 2. Cytochrome c2, cytochrome c, and ferricyanide are effective as electron acceptors with the crude enzyme but not with the purified one, whereas NAD+ and NADP+ are completely ineffective. The enzyme is thought to play a role in the electron transport system of the organism. 3. D-α-Hydroxyglutarate is virtually the sole substrate for the enzyme. The apparent activity against L-α-hydroxyglutarate is presumed to be due to contamination of the L-isomer sample with the D-isomer. The enzyme shows barely detectable activity against both isomers of malate and virtually no activity against DL-lactate and glycolate. 4. Both isomers of malate and oxalate, which are presumably substrate analogues, inhibit the enzyme activity. 5. The enzyme is not an inducible enzyme but rather is a constitutive one for R. rubrum, unlike from the enzyme of Pseudomonas putida which is an inducible enzyme for the catabolism of lysine.