2. Improvement in the histochemical localization of leucine aminopeptidase with a new substrate, L-leucyl-4-methoxy-2-naphthylamide
M M NACHLAS, B MONIS, D ROSENBATT, A M SELIGMAN J Biophys Biochem Cytol. 1960 Apr;7(2):261-4. doi: 10.1083/jcb.7.2.261.
A new method for the histochemical demonstration of leucine aminopeptidase in fresh frozen sections was developed with the substrate L-leucyl-4-methoxy-2-naphthylamide. The superior enzyme localization is due to the more rapid rate of coupling of the hydrolysis product, 4-methoxy-2-naphthylamine as compared to 2-naphthylamine itself, and to the low lipid solubility and high substantivity for protein of the copper chelate of the dye formed on coupling with tetrazotized diorthoanisidine. A comparison of the old and the new method is illustrated, and a description is given of the localization of leucine aminopeptidase in the tissues of the rat and man.
