Studies on temperature corrections for lactate dehydroge ase activity (I)

Abstract

Correction of temperature coefficient for lactate dehydrogenase (LDH) activity in human serum was studied.
In the case of healthy serum, it was identical with the value reported by Henry et al4). However, the value of coefficient factor was markdly different when serum with high LDH activity was employed. Moreover, when sera from patients with myocardial infarction and hepatitis were assayed, two values of coefficient factor were affected remarkably significant by temperature variation.
According to an Arrhenius plot, it showed two phases, namely the straight line based on activity was sharpened steeply and sharpened gently later as the temperature rose. The break occurs around 40°C, where the enzyme molecule appears to start to unravel slowly.
From the facts described above, it was consumed that enzyme might be denatured at considerably lower temperature than that reported by others and, it was moreexactly value that the coefficient factor was obtained at the temperature from 25°C to 40°C.