Nutrient utilization in actinomycetes. Induction of α-glucosidases in Streptomyces venezuelae

Abstract

Streptomyces venezuelae contains intracellular α-glucosidases that are induced during growth on maltose, isomaltose, maltotriose, dextrin, starch, and other α-glucosides. Induction was prevented by rifampicin at 10 μg∙mL−1 and inhibited by chloramphenicol or streptomycin, indicating that de novo synthesis of messenger ribonucleic acid and protein was required. Glucose and other readily utilizable sugars did not repress induction of α-glucosidase activity whereas certain organic acids and amino acids effectively reduced enzyme synthesis. Extracts of mycelium grown in the presence of maltose as an inducer hydrolysed maltose and isomaltose rapidly. Sucrose and other α-glucosides were less suitable substrates whereas trehalose and starch were not hydrolysed. No activity was observed with β-glucosides, α-galactosides, or methyl α-mannoside.