Determination of Cysteine Activated Creatine Kinase in Serum

Abstract

A coupled optical test is described to determine creatine kinase in serum. Addition of L-cysteine was used to activate the enzyme. After addition of L-cy steine 2-5 times higher values were measured. All normal sera showed measurable activity. The kinectics of serum creatine kinase were studied and compared with the data published previously. Normal values for age groups were established. In cord blood very high activities were demonstrated. Low values are found in children of 1-5 years, no sex difference in the creatine kinase activity is present until the age of ten. In adolescents and adults much higher values were observed in males than in females.