Cloning of the Malic Enzyme Gene from Corynebacterium glutamicum and Role of the Enzyme in Lactate Metabolism

AUTOR(ES)

Gourdon, Pierre

FONTE

American Society for Microbiology

RESUMO

Malic enzyme is one of at least five enzymes, known to be present in Corynebacterium glutamicum, capable of carboxylation and decarboxylation reactions coupling glycolysis and the tricarboxylic acid cycle. To date, no information is available concerning the physiological role of the malic enzyme in this bacterium. The malE gene from C. glutamicum has been cloned and sequenced. The protein encoded by this gene has been purified to homogeneity, and the biochemical properties have been established. Biochemical characteristics indicate a decarboxylation role linked to NADPH generation. Strains of C. glutamicum in which the malE gene had been disrupted or overexpressed showed no detectable phenotype during growth on either acetate or glucose, but showed a significant modification of growth behavior during lactate metabolism. The wild type showed a characteristic brief period of exponential growth on lactate followed by a linear growth period. This growth pattern was further accentuated in a malE-disrupted strain (ΔmalE). However, the strain overexpressing malE maintained exponential growth until all lactate had been consumed. This strain accumulated significantly larger amounts of pyruvate in the medium than the other strains.

Documentos Relacionados

• Characterization of the isocitrate lyase gene from Corynebacterium glutamicum and biochemical analysis of the enzyme.
• Molecular cloning and nucleotide sequence of the Corynebacterium glutamicum pheA gene.
• Cloning, sequence analysis, expression, and inactivation of the Corynebacterium glutamicum icd gene encoding isocitrate dehydrogenase and biochemical characterization of the enzyme.
• Nucleotide sequence of the dapA gene from Corynebacterium glutamicum.
• Cloning vector system for Corynebacterium glutamicum.