Comparison of four purified extracellular 1,4-beta-D-glucan cellobiohydrolase enzymes from Trichoderma viride

Four electrophoretically distinct 1,4-beta-D-glucan cellobiohydrolase enzymes (exo-cellobiohydrolase, EC 3.2.1.91) from Trichoderma viride have been purified to homogeneity. Three enzymes (A, B, and C) were from a commercial T. viride preparation whereas the other (D) was from T. viride QM 9123 grown on cellulose in submerged culture. The enzymes were similar with respect to ultraviolet light absorption, amino acid and amino sugar composition, heat stability, molecular weight, specific activity, and carboxyterminal residues, indicating very nearly identical polypeptide portions. The enzymes also exhibited immunological cross-reactivity. The enzymes differed most in the content and composition of covalently bound neutral carbohydrate.