High molecular mass forms have been reported for many serum enzymes measured in clinical laboratories. They are described as either type-1 (a normal enzyme complexed with an immunoglobulin by an antigen-antibody reaction) or type-2 macroenzymes (all other). They are detected in patients examined for persistently increased levels using electrophoretic, chromatographic or immunoinhibition methods, but are indistinguishable from normal enzymes in routine quantitative assays [1].
