M17 leucine aminopeptidase of the human malaria parasite Plasmodium vivax.
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.
Lee
Jung-Yub
JY
Department of Parasitology, Kyungpook National University School of Medicine, 700-422, Taegu, Republic of Korea.
Song
Su-Min
SM
Seok
Ji-Woong
JW
Jha
Bijay Kumar
BK
Han
Eun-Taek
ET
Song
Hyun-Ouk
HO
Yu
Hak-Sun
HS
Hong
Yeonchul
Y
Kong
Hyun-Hee
HH
Chung
Dong-Il
DI
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
D015800:Protozoan Proteins; D007931:Leucyl Aminopeptidase