Biochemical characterization of a Ca2+-dependent acid trehalase activity from the thermophilic fungus Chaetomium thermophilum var. coprophilum

A trehalase activity was purified from the mycelium of Chaetomium thermophi lum var. corpophilum. The enzyme was composed of two identical polypeptides of apparent molecular mass of 98 kDa. The pi of the enzyme was about 3.9. The purified trehalase was stimulated by calcium, manganese and cobalt and inhibited by EDTA, ADP and ATP. The enzyme exhibited a K-m of 0.63 mM, opti mum pH of 6.5, and optimum temperature of 55 degrees C. The C. thermophilum trehalase is another example of calcium-dependent, thermophilic acid treha lases which exhibit mixed properties of regulated (neutral) and nonregulate d (acid) trehalases. (C) 1999 Federation of European Microbiological Societ ies. Published by Elsevier Science B.V. All rights reserved.