[Synthesis and properties of carrier-bound enzymes. XI. Fixation of trypsin to various cellulose derivatives. Comparison of the kinetic properties of the trypsin-cellulose complexes].

Trypsin was covalently bound to carboxymethyl cellulose (CMC) azide and dialdehyde cellulose (DAC). Thereby the maximum protein binding capacity of CMC (420 mg/g) is 28 times that of DAC (15 mg/g). The high protein binding capacity of CMC is explained by a change in structure, i. e. by surface increase of the original cellulose powder due to chemical modification. By activation with sodium bisulfite solution we achieved an increase in protein binding capacity of DAC to values similar to those of CMC. The value of Vmax for all trypsin-DAC-complexes is about 38% of that of the free enzyme. With increasing protein content (from 1 to 12 mg/g) Km rises continuously from 0,14 to 0.36 mM. An analogous kinetic behaviour was found for trypsin-CMC-complexes only up to a protein content of 100 mg/g. Offering larger quantities of trypsin the enzyme is immobilized in an active form, so that all trypsin-CMC-complexes from 100 mg/g upwards have the same specific activity and the same Km; on the other hand the value of Vmax for the immobilized trypsin decreases to 17% of that for the free enzyme.