Analytical patterns and biochemical properties of macro creatine kinase type 2. Clin Chem

Here we describeour findingsfor 105 patients ’ sera contain-ing macro creatine kinase (CK) type 2, as confirmed by exclusion chromatography. Depending on the technique used for determiningisoenzyme CKs (electrophoresis,ion-exchange chromatography,immunoinhibition),this variant CK shows characteristicpatterns and interferes in CK-MB assaysbydifferentmechanismsandto variousdegrees,thus complicating test interpretation.MacroCK type 2 evidentlyis notof cytoplasmicorigin;ratherit is a separate CK activityof human serum, characterized by its heat stability arid, espe-cially, by its increased molecularmass and high energy of activation. These latter characteristics have never been associated with the normal-size, dimeric cytoplasmic CK isoenzymes, but are typical for mitochondrial CK isolated from human tissues. We conclude that mitochondrial C