Three kinds of amylase inhibitor (S-AI, S-GI and Haim) were obtained from the culture filtrate of Streptomyces sp. S-AI was produced by St, diastaticus subsp, amylostaticus and inhibited glucoamylase and various a-amylases . S-PI consisted., of 6 moles of glucose and 1 mole of unknown substances. The structure of S-AI was discussed. S-GI was a specific inhibitor for exotype glucanase and was produced by St, lavendulae . S-GI inhibited animal invertase, but did not inhibit microbial invertase. Haim was a proteineous inhibitor and produced by, St, griseosporus. Haim inhibited specifically animal a-amylases.
