Some Properties of Amylase Inhibitor A Produced byStreptomycessp. No. 280

Abstract
Streptomyces sp. No. 280 produced several kinds of amylase inhibitors (amylase inhibitor A, B, B' and C). Two amylase inhibitors (designated as AI-A1 and AI-A2) were obtained from an amylase inhibitor A fraction by paper chromatography. AI-A1 inhibited muscle phosphorylase a much more than AI-A2 and was hydrolyzed by sweet potato β-amylase whereas AI-A2 was not. Both amylase inhibitors had a carbohydrate and were hydrolyzed by some kinds of amylases or acids. They lost their inhibitory activity against phosphorylase a after treatment with acids or hog pancreatic α-amylase, but they showed increased inhibitory activity toward porcine small intestinal sucrase. Both AI-A1 and AI-A2 were composed of glucose and a basic moiety which gave a positive ninhydrin reaction. The molecular weights of AI-A1 and AI-A2 were estimated to be approximately 1300 ˜ 1500 by gel filtration on a Sephadex G-15 column. The nitrogen content of the amylase inhibitors was found to be about 1.3% by elementary analysis