[Comparison between leucyl aminopeptidase and pseudo leucine aminopeptidase activities in sera].

The highest activities of leucyl aminopeptidase(LAP, cytosol aminopeptidase, EC 3.4.11.1) in sera have been found in patients with acute hepatitis(Kanno et al., Am J Clin Path, 82: 700-705, 1984). I observed inpatients with very high activities of LAP and alcohol dehydrogenase(AD) in sera. However, only slight elevations of serum pseudo leucine aminopeptidase(PLA), that is, membrane alanyl aminopeptidase(MAA, microsomal aminopeptidase, EC 3.4.11.2) activities for hydrolysis of leucyl-4-nitroanilide were observed in these patients. They were patients in critical care unit with ischemia caused by a cardiopulmonary arrest, multiple trauma, acute myocardial infarction or operation. Therefore, we should measure LAP activities in sera rather than PLA(MAA) activities in these patients.