MANY enzymes formerly considered to be single entities are now known to be composed of a varying number of molecular forms—"isoenzymes."1 Isoenzymes act on the same substrate and produce the same end products but differ from each other in certain physicochemical characteristics determined by their molecular heterogeneity. Distinctive isoenzyme patterns have been delineated for at least 30 enzymes, but relatively few of these have direct clinical applicability of this time. Foremost among the latter are the isoenzymes of lactic dehydrogenase (LDH), amylase, and alkaline phosphatase.
The present report, based primarily on clinicopathological data from the clinical laboratories of the University of Michigan Medical Center, is a contemporary assessment of the clinical usefulness of isoenzymes in serum as they relate to surgical diagnosis and treatment.
Materials and Methods
Enzymoelectrophoresis of the isoenzymes of LDH has been done in the clinical laboratories (Section of Clinical Chemistry), University of Michigan Medical Center,