Macroenzymes: Biochemical characterization, clinical significance, and laboratory detection

Abstract

Much has been learned about macroenzymes since the first report of macroamylase 25 years ago. It is now known that conversion of serum enzymes to higher-molecular-mass forms is a general phenomenon that can involve most of the serum enzymes that are routinely measured in clinical laboratories. In addition, the biochemical characterization of the interaction between immunoglobulins and enzymes has been carefully explored, as well as the association of the hepatobiliary macroenzymes with lipoproteins and plasma membrane fragments. There is, however, a general level of ignorance about macroenzymes, perhaps because of the lack of a clear role of macroenzymes in the pathogenesis of disease. A greater understanding of autoimmunity in general and anti-enzyme antibody formation in particular will, we hope, resolve the role of macroenzymes in disease. The investigation of macroenzymes as diagnostic markers is currently an acitve area of research, which may in the future result in the development of new markers for disease and may bring the subject of macroenzymes to the forefront of clinical laboratory testing. At this time, macroenzymes are important, at the very least because of their potential to interfere with interpretation of serum enzyme results. We encourage clinicians to consider macroenzymes in the differential diagnosis of elevated serum enzyme activity, and for clinical laboratory scientists to provide effective means for detecting macroenzymes.