Human aminopeptidases: a review of the literature

The aminopeptidases constitute a group of enzymes with closely related activities. In clinical chemistry the analysis of the aminopeptidases and of their multiple forms in serum has for a long time been hindered by considerable confusion concerning their identification, and by a lack of characterization. This is in part due to the often large, and sometimes overlapping substrate specificities of the aminopeptidases. This paper reviews the biochemical properties of the different aminopeptidases, the specificities of the assays used for their analysis in serum, some aspects of their multiple forms--which are especially known to occur for alanine aminopeptidase (EC 3.4.11.2)--and the importance of the determination of aminopeptidases and their multiple forms in clinical chemistry.