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

Streptomyces venezuelae contains intracellular alpha-glucosidases that are induced during growth on maltose, isomaltose, maltotriose, dextrin, starch, and other alpha-glucosides. Induction was prevented by rifampicin at 10 micron g.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 alpha-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 alpha-glucosides were less suitable substrates whereas trehalose and starch were not hydrolysed. No activity was observed with Beta-glucosides, alpha-galactosides, or methyl alpha-mannoside.