The predominant molecular state of bound enzyme determines the strength and type of product inhibition in the hydrolysis of recalcitrant polysaccharides by processive enzymes.

ABSTRACT: Processive enzymes are major components of the efficient enzyme systems that are responsible for the degradation of the recalcitrant polysaccharides cellulose and chitin. Despite intensive research, there is no consensus on which step is rate-limiting for these enzymes. Here, we performed a comparative study of two well characterized enzymes, the cellobiohydrolase Cel7A from Hypocrea jecorina and the chitinase ChiA from Serratia marcescens. Both enzymes were inhibited by their disaccharide product, namely chitobiose for ChiA and cellobiose for Cel7A. The products behaved as noncompetitive inhibitors according to studies using the (14)C-labeled crystalline polymeric substrates (14)C chitin nanowhiskers and (14)C-labeled bacterial microcrystalline cellulose for ChiA and Cel7A, respectively.

SUBMITTER: Kuusk S 

PROVIDER: S-EPMC4416869 | biostudies-literature | 2015 May

REPOSITORIES: biostudies-literature