REGULATION OF A THERMOSTABLE ALPHA-AMYLASE OF STREPTOMYCES-THERMOVIOLACEUS CUB74 - MALTOTRIOSE IS THE SMALLEST INDUCER

We have examined induction and repression by various sugars and carbon sources of the synthesis of a thermostable alpha-amylase in its natural host, S thermoviolaceus CUB74. The smallest molecule capable of inducing synthesis of the enzyme was maltotriose whereas maltose had no effect which might suggest a different control system from that found in other streptomycete amylases. Addition of mannitol to the growth medium impeded the alpha-amylase induction whereas glucose had no effect. After cloning of its gene into a new streptomycete host, S lividans TK24, the S thermoviolaceus alpha-amylase could not be induced by any of the sugars tested.