Synthesis of Protocatechuate Oxygenase by Pseudomonas fluorescens in the Presence of Exogenous Carbon Sources

Abstract

Kirkland, Jerry J. (Oklahoma State University, Stillwater), and Norman N. Durham . Synthesis of protocatechuate oxygenase by Pseudomonas fluorescens in the presence of exogenous carbon sources. J. Bacteriol. 90: 15–22. 1965.—The addition of glucose, ribose, or fructose (0.45 or 45.0 μmoles/ml) simultaneously with protocatechuic acid shortens the lag period required for synthesis of protocatechuate oxygenase by a washed-cell suspension of Pseudomonas fluorescens . Glucose is readily oxidized and supports growth of P. fluorescens , whereas neither ribose nor fructose readily supports growth. High glucose concentrations (45.0 μmoles/ml) shorten the lag period but lower the total enzyme synthesis. The p H drops during glucose oxidation, and this is accompanied by a decrease in the rate of enzyme synthesis. High glucose concentrations, with adequate buffering, permitted “normal” enzyme synthesis. A decrease in the total enzyme synthesis was not observed in the presence of high concentrations of ribose or fructose. Succinate, pyruvate, acetate, or formate (0.45 μmole/ml) were readily oxidized, but did not shorten the lag period required for synthesis of the enzyme. The data suggest that glucose, ribose, or fructose may serve as a “specific” carbon source (such as ribose-5-phosphate or a similar precursor important in ribonucleic acid synthesis) functional in the synthesis of protocatechuate oxygenase.