Creatine kinase measurement in the 1977 CAP Enzymology Survey: anomalies explained.

In the recently published results of the 1977 College of American Pathologists Enzymology Survey, Some anomalous results were obtained in measuring the creatine kinase (EC 2.7.3.2) activity of the samples. The cause of these anomalies was discovered to be an arginine kinase (EC 2.7.3.3) contaminant in one of the enzyme pools used to make the samples. The contaminant shows cross reactivity with creatine phosphate and is activated by dithioerythritol but not the other commonly used thiol activators.