Kinetics of lactate dehydrogenase and other enzyme studies in human serum in leukemia.

The activity of some of the clinically important enzymes was investigated in leukemic sera at 37 degrees, using the Beckman Enzyme Activity Analyzer were found to be slightly elevated in some untreated cases of leukemia (1.), while ALP was found to be frequently elevated. Untreated patients with l. had normal or below normal SCPK activity. The most characteristic and significant rise in activity, was found to be associated with SLDH and SHBDH in most cases of acute l. (86%) and in CML, while any elevation observed in CLL, was very slight. The general kinetic parameters of SLDH and SHBDH, were investigated at 37 degrees in acute leukemic patients. These included optimum substrate concentrations (NADH, pyruvate, and 2-oxobutyrate), the rate of pyruvate and 2-oxobutyrate reduction, substrate-velocity relationship, Km (pyruvate), Km (NADH), Km (2-oxobutyrate) as well as the effect of temperature and pH on the kinetics of the reaction. These kinetic characteristics were found to be differently affected by the leukemic process.