Premium
Temperature dependence of a diffusion‐limited immobilized enzyme reaction
Author(s) -
Buchholz K.,
Rüth W.
Publication year - 1976
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260180108
Subject(s) - chemistry , substrate (aquarium) , activation energy , diffusion , reaction rate , immobilized enzyme , kinetics , hydrolysis , enzyme kinetics , michaelis–menten kinetics , reversible reaction , trypsin , thermodynamics , enzyme , chromatography , analytical chemistry (journal) , enzyme assay , catalysis , organic chemistry , active site , oceanography , physics , quantum mechanics , geology
The apparent activation energy of N ‐α‐benzoyl‐ L ‐arginine‐ethyl ester (BAEE) hydrolysis by immobilized trypsin varies with the bulk substrate concentration from its maximum value, comparable to that of the free enzyme, to considerably lower values. Thus, with a concentration change from 3 × 10 −2 to 10 −4 M the apparent activation energy diminishes from 9.5 to 4.5 kcal/mol. This experimental finding is interpreted to be due to Michaelis‐type kinetics in a heterogeneous system, in one case reflecting the temperature dependence of the maximal enzyme reaction rate, in another case illustrating the diffusion limited overall reaction at low substrate concentrations. As a consequence it may not be feasible to operate a reaction at elevated temperatures in a high conversion range, since diffusion limitation may restrict the enhancement of the overall reaction rate. Some further data are given concerning the buffer effect on the reaction rate, which should occur due to its limitation by proton transfer in the buffer‐free system.