CO2-fixing Enzymes in Pseudomonas fluorescens

• Published in: Journal of general microbiology Vol. 93; no. 1; pp. 69 - 74
• Main Authors: Higa, Azucena I, de Forchetti, Silvia R. Milrad, Cazzulo, J. J
• Format: Journal Article
• Language: English
• Published: England Soc General Microbiol 01-03-1976
• Subjects: Acetates - metabolism; Acetyl Coenzyme A - pharmacology; Aspartic Acid - pharmacology; Carbon Dioxide - metabolism; Carboxy-Lyases - metabolism; Cell-Free System; Enzyme Repression; Glucose - metabolism; Glutamates - metabolism; Malate Dehydrogenase - metabolism; Phosphoenolpyruvate Carboxykinase (GTP) - metabolism; Pseudomonas fluorescens - enzymology; Pseudomonas fluorescens - metabolism; Pyruvate Carboxylase - metabolism; Temperature
• ISSN: 0022-1287
• DOI: 10.1099/00221287-93-1-69

Departamento de Bioquímica, Facultad de Ciencias Bioquímicas, Universidad Nacional de Rosario, Suipacha 531, Rosario, Argentina
ABSTRACT
SUMMARY: Pseudomonas fluorescens grown on glucose or glutamate at 1 or 20 °, or on acetate at 20 °, as sole carbon sources, contained both pyruvate carboxylase and phosphoenolpyruvate carboxylase. Pyruvate carboxylase was insensitive to acetylcoenzyme A and L-aspartate, and its level in cell-free extracts was markedly dependent on the carbon source for growth, the highest specific activity being attained in glucose-grown cells. Phosphoenolpyruvate carboxylase, on the other hand, although less dependent on the nature of the carbon source, showed its highest level in acetate-grown cells; the enzyme activity required acetyl-coenzyme A and was strongly inhibited by L-aspartate. The micro-organism had, in addition, a phosphoenolpyruvate carboxykinase, which showed its highest specific activity in cells grown on acetate, and a NADP-linked malate enzyme, apparently repressed by acetate and showing its highest specific activity in glutamate-grown cells.