Premium
Flow kinetics of L ‐asparaginase attached to nylon tubing
Author(s) -
Bunting Peter S.,
Laidler Keith J.
Publication year - 1974
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.260160109
Subject(s) - diffusion , chemistry , kinetics , ionic strength , substrate (aquarium) , volumetric flow rate , ammonia , chromatography , chemical engineering , analytical chemistry (journal) , thermodynamics , organic chemistry , aqueous solution , physics , oceanography , quantum mechanics , geology , engineering
Abstract L ‐Asparaginase has been attached by chemical means to the inner surface of nylon tubing. An experimental study has been carried out of the flow kinetics for such a system, asparagine solutions at various concentrations being passed through two lengths of tubing at various flow rates. Measurements were made of the concentration of the product ammonia at the tube exit, and of the rate of formation of ammonia, under the various conditions. Apparent Michaelis constants, K m (app), were some three orders of magnitude higher than the K m for the enzyme in free solution (∼13 × 10 −6J M ). The results were analyzed with respect to the theoretical treatment described in the preceding paper (Kobayashi and Laidler), three different methods being employed. It is concluded that at lower substrate concentrations and flow rates the reactions are largely diffusion‐controlled, the enhanced K m (app) values being largely if not entirely due to the diffusion control; ionic strength studies showed electrostatic repulsion effects to be unimportant. At high concentrations and high flow rates (when the diffusion layer is of negligible thickness) the diffusional effects are minimized, and K m (app) approaches the true K m value for the immobilized enzyme.