[Macroenzymes in human plasma. 1: Macroamylase, macrocreatine kinase, macrolactate dehydrogenase]

The authors propose here a general review of the main macroenzymes described until now. In this first part, informations will be given about the high molecular forms of alpha amylase, creatine kinase (CK) and lactate dehydrogenase (LDH) found in human plasma. Except macro CK type 2 which can be related to the mitochondrial CK, these macroenzymes are the result of the formation of enzyme immunoglobulin complexes; their specific immune character has been demonstrated in some cases. The formation of such immune complexes between the enzyme protein and plasma immunoglobulins seems a rather common phenomenon although neither the mechanism involved nor the physiopathological significance are known since they have been observed in patients and healthy individuals. Nevertheless, it is important to recognize these macromolecular forms because of the diagnostic uncertainties they may induce during isoenzyme studies and even total enzyme activity measurement.