Kinetics of enzymatic hydrolysis of sodium carboxymethylcellulose with different degrees of polymerization by cellulase

摘要

The reaction cellulase (EC 3.2.1.4)—sodium carboxymethylcellulose (Na-CMC) with different degrees of polymerization (n=140, 640 and 900) was investigated by the use of a modifiedMichaelis-Mentenequation, valid for enzymatic hydrolysis of linear homopolymers. TheMichaelis-Mentenconstant Km′(M)=6.31·10−2mol/dm3 and the reaction rate constant (k′+2=4.07·10−6s−1), which correspond to the enzymatic hydrolysis of a single bond in the homopolymer substrates are determined. The free energy (Δ$$G^{ = } $$=101 kJ/mol), which corresponds to the degradation and formation of a single bond in the enzyme—polymer substrate is also estimated. This energy expressed in electronvolt units is Δ$$E^{ = } $$=1.39 eV. The ratio between the effective cross section of the reactive substrate bond and the active enzyme