The amylase and maltase of Clostridium acetobutylicum

Abstract

Cell-free culture filtrates of C. acetobutylicum convert starch quantitatively to glucose. This conversion is brought about by the successive action of an amylase and a maltase. The amylase has an optimum pH at 4.8, is not affected by KCN, MgCl2, NaF, NaH2AsO4, iodoacetic acid, phlorrhizin, maltose, inulin, cysteine and catechol in concns. of 0.01 M. Inhibition by 0.01 M ascorbic acid and dihydroxymaleic acid was reversed by 0.02 M KCN. It hydrolyses dextrin and gly-cogen but not inulin. A relatively maltase-free prepn. would slow down as the reducing groups liberated approached 100% maltose. The maltase had an opt. pH at 4.5, and maximal velocity of hydrolysis at 0.02 M maltose. Conversion of maltose to glucose was confirmed by isolation of glucosazone.