The hydrolysis of barley beta-glucan by the cellulase EC 3.2.1.4 under dilute conditions is identical to that of barley solubilase.

Barley beta-glucan solubilase is an enzyme that degrades barley beta-glucan in extracts obtained from barley flour. The solubilase preferentially attacks the longer blocks of beta-(1-->4) linkages, i.e., those containing at least nine glucosyl residues. There is strong evidence to suggest that the solubilase derives from fungi associated with the husk of the grain. It was found that cellulase (EC 3.2.1.4) from Trichoderma sp. shows similar activity under dilute conditions. Since fungi associated with the husk of the grain are known to produce these types of cellulases, there is no need, based on current evidence, to propose the existence of a unique enzyme, i.e., solubilase, for the solubilising behaviour of enzymes in the barley grain.