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Functional characterization of X-prolyl aminopeptidase from Toxoplasma gondii

  • MINGFA YANG (a1) (a2), JUN ZHENG (a2), HONGLIN JIA (a2) and MINGXIN SONG (a1)


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.


Corresponding author

*Corresponding authors: College of Veterinary Medicine, Northeast Agricultural University, Mucai Street 59, Xiangfang District, Harbin 150001, People's Republic of China. Tel: +8613059000733. E-mail: and Harbin Veterinary Research Institute, CAAS-Michigan State University Joint Laboratory of Innate Immunity, State Key Laboratory of Veterinary Biotechnology, Chinese Academy of Agricultural Sciences, Maduan Street 427, Nangang District, Harbin 150001, People's Republic of China. Tel: +8618946066070. E-mail:


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