Đang chuẩn bị liên kết để tải về tài liệu:
Báo cáo khoa học: Inorganic pyrophosphatase in the roundworm Ascaris and its role in the development and molting process of the larval stage parasites

Inorganic pyrophosphatase (PPase) is an important enzyme that catalyzes the hydrolysis of inorganic pyro-phosphate (PPi)intoortho-phosphate (P i ). We report here the molecular cloning and characterization of a gene encoding the soluble PPase of the roundworm Ascaris suum. The predicted A. suumPPase consists of 360 amino acids with a molecular mass of 40.6 kDa and a pI of 7.1. Amino acid sequence alignment and phylogenetic analysis indicates that the gene encodes a functional Family I soluble PPase containing features identical to those of prokaryotic, plant and animal/fungal soluble PPases | Eur. J. Biochem. 270 2814-2826 2003 FEBS 2003 doi 10.1046 j.1432-1033.2003.03658.x Inorganic pyrophosphatase in the roundworm Ascaris and its role in the development and molting process of the larval stage parasites M. Khvrul Islam1 Takeharu Mivoshi1. Harue Kasuaa-Aoki1 Takashi Isobe1 Takeshi Arakawa2 Yasunobu Matsumoto3 and Naotoshi Tsuji1 1 Laboratory of Parasitic Diseases National Institute of Animal Health National Agricultural Research Organization 3-1-5 Kannondai Tsukuba Ibaraki Japan 2Division of Molecular Microbiology Center of Molecular Biosciences University of the Ryukyus Senbaru Okinawa Japan 3Laboratory of Global Animal Resource Science Graduate School of Agricultural and Life Sciences University of Tokyo Yayoi Bunkyo Tokyo Japan Inorganic pyrophosphatase PPase is an important enzyme that catalyzes the hydrolysis of inorganic pyrophosphate PPi into ortho-phosphate Pi . We report here the molecular cloning and characterization of a gene encoding the soluble PPase of the roundworm Ascaris suum. The predicted A. suum PPase consists of 360 amino acids with a molecular mass of 40.6 kDa and a pI of 7.1. Amino acid sequence alignment and phylogenetic analysis indicates that the gene encodes a functional Family I soluble PPase containing features identical to those of prokaryotic plant and animal fungal soluble PPases. The Escherichia coli-expressed recombinant enzyme has a specific activity of 937 Ltmol Pi-min 1-mg-1 protein corresponding to a kcat value of 638 s-1 at 55 C. Its activity was strongly dependent on Mg2 and was inhibited by Ca2 . Native PPases were expressed in all developmental stages of A. suum. A homolog was also detected in the most closely related human and dog roundworms A. lumbricoides and Toxocara canis respectively. The enzyme was intensely localized in the body wall gut epithelium ovary and uterus of adult female worms. We observed that native PPase activity together with development and molting in vitro of A. suum L3 to L4 were .