title: Tryptophan aminopeptidase activity of several indole prenyltransferases from Aspergillus fumigatus.
abstract: Recently, five indole prenyltransferases from Aspergillus fumigatus have been proven biochemically to be responsible for prenylations of diverse substrates. In this study, we show peptidase activities of 7-DMATS, FgaPT1, CdpNPT, and FtmPT1, with preference for linear peptides containing a tryptophanyl moiety at the N terminus. Testing of 31 peptides revealed that these enzymes shared similar substrate specificity and accepted H-L-Trp-L-Ala-OH and H-L-Trp-Gly-OH as best substrates for aminopeptidase activity. By using H-L-Trp-Gly-OH as substrate, Km values at 350, 380, 300, and 420 microM and enzymatic rate constants kcat/Km at 0.51, 0.24, 0.53, and 0.14 mM(-1)s(-1) were determined for 7-DMATS, FgaPT1, CdpNPT, and FtmPT1, respectively. In contrast to prenyltransferase activities, the aminopeptidase activities were strongly or completely inhibited by EDTA. Mn2+ increased the aminopeptidase activities of FtmPT1 and CdpNPT up to 4- and 6-fold, respectively. To the best of our knowledge, this is the first report on the catalytic promiscuity of prenyltransferases.
authors.affiliation: Heinrich-Heine-Universität Düsseldorf, Institut für Pharmazeutische Biologie und Biotechnologie, Universitätsstrasse 1, D-40225 Düsseldorf, Germany.
authors.forename: Anika
authors.initials: A
authors.lastname: Kremer
authors.forename: Shu-Ming
authors.initials: SM
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000626:Aminopeptidases / Q000737:chemistry*; D001232:Aspergillus fumigatus / Q000201:enzymology* / Q000378:metabolism; D004122:Dimethylallyltranstransferase / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry; D006868:Hydrolysis; D007211:Indoles / Q000737:chemistry*; D007700:Kinetics; D008345:Manganese / Q000737:chemistry; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D014364:Tryptophan / Q000737:chemistry*
chemical_list: D007211:Indoles; D010455:Peptides; D011994:Recombinant Proteins; D008345:Manganese; D014364:Tryptophan; D004492:Edetic Acid; D004122:Dimethylallyltranstransferase; D000626:Aminopeptidases