Flow kinetics of lactate dehydrogenase chemically attached to nylon tubing

Publisher Website
Google Scholar
Abstract
Rabbit muscle lactate dehydrogenase (EC 1.1.1.27) was attached covalently to the inner surface of nylon tubing; a modified technique, involving benzidine and glutaraldehyde, was used, and the resulting immobilized enzyme showed no loss of activity over a period of several months. An experimental study was made of the flow kinetics for the reaction between pyruvate and NADH in 2 limiting cases, one substrate in excess and the concentration of the other one varied. A range of flow rates and temperatures was covered. The results were analyzed in various ways on the basis of the Kobayashi-Laidler treatment of flow systems. Apparently the kinetics are largely diffusion-controlled, especially at the lower substrate concentrations and flow rates. The values of the apparent Km vary with flow rate vf, being linear in vf-1/3, and the values extrapolated to infinite flow rate (vf-1/3 = 0) approach the values for the enzyme in free solution. Analysis of the rates led to activation energies for the diffusion of the 2 substrates.
Keywords