Action patterns and substrate-binding requirements of β- d-mannanase with mannosaccharides and mannan-type polysaccharides

Abstract

Purified (1→4)-β- d-mannanase from Aspergillus niger and lucerne seeds has been incubated with mannosaccharides and end-reduced (1→4)-β- d-mannosaccharides and, from the products of hydrolysis, a cyclic reaction-sequence has been proposed. From the heterosaccharides released by hydrolysis of the hot-water-soluble fraction of carob galactomannan by A. niger β- d-mannanase, a pattern of binding between the β- d-mannan chain and the enzyme has been deduced. The products of hydrolysis with the β- d-mannanases from Irpex lacteus, Helix pomatia, Bacillus subtilis, and lucerne and guar seeds have also been determined, and the differences from the action of A. niger β- d-mannanase related to minor differences in substrate binding. The products of hydrolysis of glucomannan are consistent with those expected from the binding pattern proposed from the hydrolysis of galactomannan.