tailieunhanh - Báo cáo khoa học: ATP N-glycosidase A novel ATP-converting activity from a marine sponge Axinella polypoides

A novel nucleosidase enzymatic activity was discovered in the marine spongeAxinella polypoides. This enzyme, desig-nated as ATP N-glycosidase, converts adenosine-5¢-tri-phosphate into adenine and ribose-5-triphosphate. The crude extract capable of hydrolysing 25lmol ATPÆmin )1 per g wet weight of sponge. The cata-lytic activity of a sponge crude extract permg total protein is comparable with specific activities of purified plant adeno-sine and bacterial AMP nucleosidases. | Eur. J. Biochem. 270 4122-4132 2003 FEBS 2003 doi ATP N-glycosidase A novel ATP-converting activity from a marine sponge Axinella polypoides Tonu Reintamm Annika Lopp Anne Kuusksalu Tonis Pehk and Merike Kelve Laboratory of Molecular Genetics National Institute of Chemical Physics and Biophysics Tallinn Estonia A novel nucleosidase enzymatic activity was discovered in the marine sponge Axinella polypoides. This enzyme designated as ATP N-glycosidase converts adenosine-5 -tri-phosphate into adenine and ribose-5-triphosphate. The crude extract of A. polypodlss was capable of hydrolysing 25 Ltmol ATP-min-1 per g wet weight of sponge. The catalytic activity of a sponge crude extract per mg total protein is comparable with specific activities of purified plant adenosine and bacterial AMP nucleosidases. The preferred substrate for the novel enzyme is ATP but any compound containing adenosine-5 -diphosphoryl fragment is also cleaved. The biochemical properties Km Kip environmental requirements of ATP N-glycosidase show similarities with previously described adenine-specific nucleosidases however the pattern of its biochemical characteristics does not match with that of any of those enzymes. Keywords adenosine nucleotide metabolism ATP Axinella polypoides marine sponge nucleosidase. Most of the biological and chemical literature concerning marine sponges is primarily dedicated to the isolation and characterization of exotic secondary metabolites and studies of their biological activity antibacterial antifungal anticancer etc. 1 . These works have been rooted and inspired by the discovery of unusual nucleosides in Cryptotethya crypta-arabinothymidine and -uridine 2 which have led to the development of pharmaceuticals with antiviral and anticancer action. We have shown the presence of 2 5 -oligoadenylates 2-5A in a marine sponge Geodia cydonium 3 . The synthesis of 2-5A from ATP in sponges proceeds independently from dsRNA 4 in contrast with