[Macroenzymes in human plasma. 2. Macrogamma-glutamyltransferase, macroalanine aminopeptidase, macroalkaline phosphatase, macroaminotransferases and other macroenzymes].

The authors propose here the second part of the review concerning the plasma macroenzymes. Informations are given about the high-molecular mass forms of gamma-glutamyltransferase (GGT), alanine aminopeptidase (AAP), alkaline phosphatase (ALP), aminotransferase, acid phosphatase and glucose-6-phosphatase dehydrogenase. For almost all these enzymes, the presence of enzyme-immunoglobulins complexes may be observed in some plasma, but a specific immune character of these complexes has not always been proved. The membrane origin of GGT, AAP and ALP is responsible for the existence of special circulating macroforms: enzyme-lipoproteins associations due to the amphiphilic nature of some forms of these enzymes, and complexes between enzymes and membrane components. Although the knowledge about the structure of all these macroenzymes is increasing, the clinical interest to consider their existence because of the diagnostic uncertainties they may induce.