Separation of creatine kinase isoenzymes in serum by ion-exchange column chromatography (Mercer's method, modified to increase sensitivity).

We describe our experience with Mercer's method [Clin. Chem. 20, 36 (1974)] for separating isoenzymes of creatine kinase (EC 2.7.3.2) in serum by ion-exchange chromatography. By using diethylaminoethyl cellulose rather than diethylaminoethyl Sephadex in the column and by changing the ionic strength of the eluting buffer, we could detect a significant proportion of the MB isoenzyme of serum creatine kinase at normal activities of creatine kinase in serum, even in the absence of cardiac disease.