An assay for selective determination of exo-1,4,-β-glucanases in a mixture of cellulolytic enzymes

✍ Scribed by Mukund V. Deshpande; Karl-Erik Eriksson; L. Göran Pettersson

• Publisher: Elsevier Science
• Year: 1984
• Tongue: English
• Weight: 587 KB
• Volume: 138
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(84)90843-1

✦ Synopsis

A selective procedure using synthetic substrates for determination of exo-1,4,-beta-glucanases in a mixture of exoglucanases , endoglucanases , and beta-glucosidases is formulated. The heterobiosides , p- nithrophenyl -beta-D- cellobioside ( pNPC ) or p-nitrophenyl-beta-D-lactoside ( pNPL ), were used as selective substrates for the measurement of exoglucanase activity. The exoglucanases (especially cellobiohydrolases , which split off cellobiose units from the nonreducing end of the cellulose chain) specifically act on the agluconic bond (between p-nitrophenyl and the disaccharide moiety) and not on the holosidic bond (between the two glucose units of cellobiose). The interfering effect of beta-glucosidase, which acts on both agluconic and holosidic bonds, is overcome by the addition of D-glucono-1,5-delta-lactone, a specific inhibitor of beta-glucosidases. The interference of endoglucanases , which also act on both agluconic and holosidic bonds, can be compensated for by prior standardization of the assay procedure with a purified endoglucanase from the studied mixture of cellulases.