title: Functional characterization of X-prolyl aminopeptidase from Toxoplasma gondii.
abstract: In the present study, a recombinant aminopeptidase P (rTgAPP) from Toxoplasma gondii was expressed in Escherichia coli to evaluate its enzyme parameters. The rTgAPP showed strong activity against a synthetic substrate for aminopeptidase P at pH 8·0 with a K m value of 0·255 µ m and a k cat value of 35·6 s-1. The overall catalytic efficiency (k cat/K m) of the rTgAPP was 139·6 × 105 M-1 s-1. The activity of rTgAPP was enhanced by the addition of divalent cations and inhibited by bestatin. Deletion of TgAPP gene in the parasite through a CRISPR/Cas9 system resulted in inhibition of growth indicating the importance of TgAPP. Thus our findings reveal that TgAPP is an active enzyme in T. gondii and provide an insight into the function of TgAPP.
authors.affiliation: College of Veterinary Medicine, Northeast Agricultural University,Harbin,Heilongjiang,China.
authors.forename: Mingfa
authors.initials: M
authors.lastname: Yang
authors.affiliation: Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences,Harbin,China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zheng
authors.affiliation: Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences,Harbin,China.
authors.forename: Honglin
authors.initials: H
authors.lastname: Jia
authors.affiliation: College of Veterinary Medicine, Northeast Agricultural University,Harbin,Heilongjiang,China.
authors.forename: Mingxin
authors.initials: M
authors.lastname: Song
mesh_terms: D000626:Aminopeptidases / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism*; D000818:Animals; D055162:Biocatalysis; D002412:Cations; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D007700:Kinetics; D007930:Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D014122:Toxoplasma / Q000201:enzymology* / Q000235:genetics
chemical_list: D002412:Cations; D015800:Protozoan Proteins; D011994:Recombinant Proteins; D000626:Aminopeptidases; C022750:X-Pro aminopeptidase; D007930:Leucine; C012211:ubenimex
keywords: Toxoplasma gondii; Toxoplasmosis; X-prolyl aminopeptidase; enzymatic activity; growth