Thermal analysis of blood catalase reaction.

Abstract

By the thermal analysis of reaction velocity, the catalytic decomposition of the hydrogen peroxide solution by blood catalase (red cell suspension and hemolysate) has been studied, especially the effect of the hydrogen peroxide concentration and that of the blood catalase concentration, with the effect of temperatures (20°-40°C.), and the reaction process was discussed from the standpoint of the adsorption theory and thediffusion theory. The results obtained are asfollows.(1) It has beenfound that the reaction proceeds generally in threestages: the initial stage, the steady stage, and the retarded stage. The duration of the initial stage is practically independent of the concentration of hydrogen peroxide and is nearly in inverse proportion to the concentration of the blood catalase. The steady stage, which is the main part of reaction, is of the first order with respect to hydrogen peroxide, and the reaction velocity constant is proportional to the concentration of the red cell suspension and of the hemolysate.pH6.8; in the case of hemolysate caused by distilled water alone, however, it is nearly proportional to the power 1.3 of its concentration.(2) The reaction proceeds according to theequations: dx/dt=k1ae-k1t-Be-kt at its initial and steady stages, and dx/dt=ka-x√t at its retarded stage.(3) The activity of hemolysate, that is, the velocity constantof the first order reaction, k1, decreases with the time, t', in which the hemolysate was left to stand in the definite temperature. The relation between k1, and√t' is represented by thefollowing expression:logk1=e√t'+logk1in which K1 is an activity where t'=0.ΙeΙ increases with rising temperature.ΙeΙ is decreased as the concentration of hemolysate is decreased, and, between the two, the linear relation is found. In the case of red cell suspension, spontaneous deactivation is not found.(4) The apparent activation energy was found to be 7.18 Cal. in the case of red cell suspension, and 13.9 Cal. in the case of hemolysate.