Dual role of imidazole as activator/inhibitor of sweet almond (Prunus dulcis) β-glucosidase.

ABSTRACT: The activity of Prunus dulcis (sweet almond) β-glucosidase at the expense of p-nitrophenyl-β-d-glucopyranoside at pH 6 was determined, both under steady-state and pre-steady-state conditions. Using crude enzyme preparations, competitive inhibition by 1-5 mM imidazole was observed under both kinetic conditions tested. However, when imidazole was added to reaction mixtures at 0.125-0.250 mM, we detected a significant enzyme activation. To further inspect this effect exerted by imidazole, β-glucosidase was purified to homogeneity. Two enzyme isoforms were isolated, i.e. a full-length monomer, and a dimer containing a full-length and a truncated subunit. Dimeric β-glucosidase was found to perform much better than the monomeric enzyme, independently of the kinetic conditions used

SUBMITTER: Caramia S 

PROVIDER: S-EPMC5614632 | biostudies-literature | 2017 Jul

REPOSITORIES: biostudies-literature