Sensitive, rapid assay of subforms of creatine kinase MB in plasma.
The subforms of creatine kinase (CK; EC 2.7.3.2) in plasma have received recent attention as potential markers for the early diagnosis of acute myocardial infarction. Because changes in CK-MM subforms are not specific for myocardial injury, we developed an assay, based on high-voltage electrophoresis, that is sufficiently sensitive to detect the CK-MB subforms at concentrations substantially below the upper limit of normal (14 U/L). The assay can detect 1.25 U of either MB subform per liter with a precision of 0.20 U/L and gives responses that vary linearly with activity concentration from 0.0 through 30.0 U/L, with an identical signal response for both subforms. When both subforms are present in a serum sample, the assay accurately measures both the relative percentage and the absolute quantity of each: assay activity/known activity was 1.03 for each subform at a total MB subform activity of 5.0 U/L (r = 0.98). Assay time is 25 min, and there is no loss of CK during electrophoresis. Thus, this system can be used to rapidly, sensitively, and precisely quantify the two CK-MB subforms at activities well within the normal reference interval.
Puleo
P R
PR
Department of Medicine, Baylor College of Medicine, Houston, TX 77030.
Guadagno
P A
PA
Roberts
R
R
Perryman
M B
MB
D015415:Biomarkers / Q000097:blood; D003402:Creatine Kinase / Q000097:blood*; D004586:Electrophoresis / Q000379:methods; D006801:Humans; D007527:Isoenzymes; D009203:Myocardial Infarction / Q000175:diagnosis / Q000201:enzymology
D015415:Biomarkers; D007527:Isoenzymes; D003402:Creatine Kinase