Abstract
A specific method for determination of cytosol leucine aminopeptidase (CLAP) was devised, in which the ammonia libelated from L-leucine amide (LA) added as the substrate was measured with glutamate dehydrogenase added as the aid of the coupling enzyme at pH 7.6 in the presence of 1 mM o-phenanthroline.
The principle of the method is due to the present finding that o-phenanthroline inhibited arylamidase (AA) and cystyl aminopeptidase (CAP) completely at 0.6mM or higher, but not CLAP even at 1 mM.
The present method showed good correlations to the method using LA and that using Lleucyl-p-nitroanilide (L-PNA) as the substrate, except that there were remarkable discrepancies to the former method in the cases of hepatobiliary disorder and pregnancy, and those to the latter method in the cases of hepatitis, malignant lymphoma and leukemia in addition to hepatobiliary disorder and pregnancy.
This suggests that the present method was specific for CLAP, useful for clinical diagnosis.
