title: M17 leucine aminopeptidase of the human malaria parasite Plasmodium vivax.
abstract: Amino acids derived from hemoglobin are essential to protein synthesis required for growth and development of the Plasmodium vivax malaria parasite. M17 leucine aminopeptidase (LAP) is a cytosolic metallo-exopeptidase that catalyzes the removal of amino acids from the peptide generated in the process of hemoglobin degradation. Inhibitors of the enzyme have shown promise as drugs against Plasmodium infections, implicating aminopeptidases as a novel potential anti-malarial chemotherapy target. In this study, we isolated a cDNA encoding a 68kDa P. vivax LAP (PvLAP). Deduced amino acid sequence of PvLAP exhibited significant sequence homology with LAP from Plasmodium falciparum. Biochemical analysis of the recombinant PvLAP protein produced in Escherichia coli demonstrated preferential substrate specificity for the fluorogenic peptide Leu-7-amido-4-methylcoumarin hydroxide and inhibition by EDTA, 1,10-phenanthroline, and bestatin, which are conserved characteristics of the M17 family of LAP. PvLAP was optimally active at slightly alkaline pH and its activity was dependent on divalent metal ions. Based on the biochemical properties and immunofluorescence localization, PvLAP is concluded to represent a LAP in P. vivax. The enzyme is most likely responsible for the catabolism of host hemoglobin and, hence, represents a potential target of both P. falciparum and P. vivax chemotherapy.
authors.affiliation: Department of Parasitology, Kyungpook National University School of Medicine, 700-422, Taegu, Republic of Korea.
authors.forename: Jung-Yub
authors.initials: JY
authors.lastname: Lee
authors.forename: Su-Min
authors.initials: SM
authors.lastname: Song
authors.forename: Ji-Woong
authors.initials: JW
authors.lastname: Seok
authors.forename: Bijay Kumar
authors.initials: BK
authors.lastname: Jha
authors.forename: Eun-Taek
authors.initials: ET
authors.lastname: Han
authors.forename: Hyun-Ouk
authors.initials: HO
authors.lastname: Song
authors.forename: Hak-Sun
authors.initials: HS
authors.lastname: Yu
authors.forename: Yeonchul
authors.initials: Y
authors.lastname: Hong
authors.forename: Hyun-Hee
authors.initials: HH
authors.lastname: Kong
authors.forename: Dong-Il
authors.initials: DI
authors.lastname: Chung
mesh_terms: D000595:Amino Acid Sequence; D004795:Enzyme Stability; D006801:Humans; D007700:Kinetics; D007931:Leucyl Aminopeptidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D013379:Substrate Specificity
chemical_list: D015800:Protozoan Proteins; D007931:Leucyl Aminopeptidase