Purification of an aminopeptidase preferentially releasing N-terminal alanine from cucumber leaves and its identification as a plant aminopeptidase N.
In this study, a highly active foliar aminopeptidase preferentially releasing N-terminal alanine from artificial substrates was purified and characterized from cucumber (Cucumis sativus L. suyo). The enzyme had a molecular mass of 200 kDa consisting of two subunits of 95 kDa. It was a metalloprotease the pH optimum of which was 8 to 9. It cleaved Ala-, Gly-, Met-, Ser-, Leu-, Lys-, and Arg artificial substrates. An internal amino acid sequence was similar to those of aminopeptidase N (clan MA, family M1) of microorganisms, and was very similar to that of a putative aminopeptidase N of Arabidopsis thaliana. From these results, the highly active aminopeptidase in cucumber leaves was identified to be a plant aminopepitdase N.
Yamauchi
Y
Y
Faculty of Agriculture, Tottori University, Koyama, Japan. yamauchi@muses.tottori-u.ac.jp
Ejiri
Y
Y
Tanaka
K
K
D000409:Alanine / Q000378:metabolism*; D000595:Amino Acid Sequence; D000626:Aminopeptidases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D018553:Cucumis sativus / Q000201:enzymology*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D018515:Plant Leaves / Q000201:enzymology; D017386:Sequence Homology, Amino Acid
D000626:Aminopeptidases; D000409:Alanine