PMID: 234460Feb 25, 1975

Studies on the mechanism of Mycobacterium smegmatis L-lactate oxidase. 5-Deazaflavin mononucleotide as a coenzyme analogue

The Journal of Biological Chemistry
B A AverillR H Abeles

Abstract

Apo-lactic oxidase from Mycobacterium smegmatis reconstituted with the deazaisoalloxazine analogue of FMN, 5-deazaFMN, undergoes reduction by L-lactate but not catalytic reoxidation by O2. The rate of deazaFMN-holo-enzyme reduction by substrate is 1.1 min-1. With L-[alpha-3-H]-lactate, direct tritium transfer to enzyme-bound deazaFMN occurs during reduction. No evidence for a stable covalent lactate-deazaFMN adduct has been obtained. The deaza-FMNH2-enzyme is reoxidized extremely slowly by O2, consistent with the sluggish nonenzymatic reaction of deaza-FMNH2 with oxygen. On the other hand, addition of pyruvate to the deazaFMNH2-enzyme causes rapid reoxidation, a process not detected in the absence of enzyme.

Related Concepts

Alcohol Oxidoreductases
Molecular Sieve Chromatography
Flavin Mononucleotide Monosodium Salt, Dihydrate
Lactates
Genus Mycobacterium
Oxidation-Reduction
Spectrophotometry
Spectrophotometry, Ultraviolet
Tritium

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