The action of culture filtrates of the fungus Myrothecium verrucaria on β-glucosans

Abstract

Cell-free culture filtrates of M. verrucaria contain a cellulase, producing cellobiose and glucose from complex and single-chain cellulose molecules, which is partially inactivated by heating at 60[degree] for 10 min. No evidence has appeared of the existence, in these filtrates, of a further enzyme breaking down of complex cellulose into straight-chain fragments. They also contain, though not always, cello-biase, hydrolyzing cellobiose to glucose, which is completely inactivated in 10 min. at 60[degree]. When cellobiose is absent there is evidence of transglycosidase activity, producing glucose and cellotriose from cellobiose. This activity is also completely abolished by heating for 10 min. at 60[degree]. In addition to [beta]-14-glycosidases, culture filtrates of M. verrucaria contain [beta]-1:3-glycosidases, hydrolyzing laminar in and laminaribiose. When [beta]-1:3- and [beta]-1:4-ases act together on barley 0-glucosan the products are cellobiose, laminaribiose and glucose. The results obtained after the filtrate has been heated at 60[degree] for 10 min. suggest that the [beta]-1:3 and [beta]-1:4-linkages occur separately in distinct groups in the barley B-glucosan.