isoenzyme

n.
Any of the chemically distinct forms of an enzyme that perform the same biochemical function.

isoenzymic i'so·en·zy'mic adj.

Variant: isoenzyme

One of several forms of an enzyme in an individual or population that catalyse the same reaction but differ from each other in such properties as substrate affinity and maximum rates of enzyme-substrate reaction (see Michaelis-Menten curve).

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Enzymes that have the same catalytic activity, but different structures, properties, and/or tissue distribution.

Any of the several forms of an enzyme, all of which catalyze the same reaction, but which may differ in reaction rate, inhibition by various substances, electrophoretic mobility or immunological properties. Several enzymes, particularly alkaline phosphatase, lactate dehydrogenase and creatine kinase, have clinically important isoenzymes. Isoenzymes are separated by electrophoresis, and the pattern indicates which damaged organ has released the enzymes.