Identification of yeast aspartyl aminopeptidase gene by purifying and characterizing its product from yeast cells.
Aspartyl aminopeptidase (EC 3.4.11.21) cleaves only unblocked N-terminal acidic amino-acid residues. To date, it has been found only in mammals. We report here that aspartyl aminopeptidase activity is present in yeast. Yeast aminopeptidase is encoded by an uncharacterized gene in chromosome VIII (YHR113W, Saccharomyces Genome Database). Yeast aspartyl aminopeptidase preferentially cleaved the unblocked N-terminal acidic amino-acid residue of peptides; the optimum pH for this activity was within the neutral range. The metalloproteases inhibitors EDTA and 1.10-phenanthroline both inhibited the activity of the enzyme, whereas bestatin, an inhibitor of most aminopeptidases, did not affect enzyme activity. Gel filtration chromatography revealed that the molecular mass of the native form of yeast aspartyl aminopeptidase is approximately 680,000. SDS/PAGE of purified yeast aspartyl aminopeptidase produced a single 56-kDa band, indicating that this enzyme comprises 12 identical subunits.
Yokoyama
Ryo
R
Supramolecular Biology, International Graduate School of Arts and Sciences, Yokohama City University, Japan.
Kawasaki
Hiroshi
H
Hirano
Hisashi
H
D000595:Amino Acid Sequence; D000626:Aminopeptidases / Q000737:chemistry* / Q000302:isolation & purification; D000818:Animals; D002850:Chromatography, Gel; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004795:Enzyme Stability / Q000187:drug effects; D043384:Glutamyl Aminopeptidase / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D046912:Multiprotein Complexes / Q000737:chemistry / Q000302:isolation & purification; D010455:Peptides / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000302:isolation & purification; D016415:Sequence Alignment
D004791:Enzyme Inhibitors; D046912:Multiprotein Complexes; D010455:Peptides; D029701:Saccharomyces cerevisiae Proteins; D000626:Aminopeptidases; C507984:aspartyl aminopeptidase, S cerevisiae; D043384:Glutamyl Aminopeptidase