Serum level of alpha-N-acetyl-D-glucosaminidase in myocardial infarction in man.

alpha-N-acetyl-D-glucosaminidase, a lysosomal enzyme essential for the degradation of heparin sulfate, was measured in the sera of normal individuals and of 19 patients with myocardial infarction (MI). Normal individuals maintained a constant level of this enzyme from day to day. In contrast, patients with MI had a 2-3 fold elevation of this enzyme as early as 2 hr after MI. This elevation persisted at least until the creatine phosphokinase-MB had attained maximum activity, usually 6-23 hr after MI and then gradually decreased, returning to normal levels 3-5 days later.