Abstract

Three different aminopeptidases (LPAase 1, LPAase 2 and APAase) separable by DEAE-cellulose column chromatography were present in the leaves of Euonymus alatus f. ciliato-dentalus. These enzymes also were verified by polyacrylamide gel electrophoresis, and their substrate specificities were tested with aminoacyl-β-naphthylamides (aminoacyl-NAs) and aminoacyl-p-nitroanilides (aminoacyl-PAs). The enzymes LPAase 1 and LPAase 2 hydrolyzed leucine-PA (LPA) and phenylalanine-NA. APAase hydrolyzed alanine-PA (APA) and arginine-NA. LPAase 1 and LPAase 2 were not affected by 1,10-phenanthroline, whereas APAase was strongly inhibited by it. All three enzymes were inhibited by p-chloromercuribenzoate (PCMB).

In the Euonymus leaves, the total activity of the three enzymes, LPAase 1, LPAase 2 and APAase, increased as leaves senesced during autumn. The highest activity of the main enzyme, LPAase 2, was found in the leaves collected during October. A marked increase in LPAase activity was found in the red leaves collected in December.

This content is only available as a PDF.
You do not currently have access to this article.