Characterisation of a Bis(5'-nucleosidyl) triphosphate pyrophosphohydrolase from encysted embryos of the brine shrimp Artemia

Mark Prescott, N. Matthew, H. Thorne, Andrew D. Milne, Alexander G. McLennan

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1. 1. A P1,P3-bis(5'-nucleosidy)triphosphate pyrophosphohydrolase (Np3Nase) has been partially purified from Anemia embryos. 2. 2. The Np3Nase has a native Mr of 115,000 and preferentially hydrolyses substrates of the form Np3N. Relative rates of hydrolysis are Ap3A (Vrel=1.0), Gp3G (Vrel=0.71), Ap4A (Vrel1 = 0.08), Ap5A (vrel = 0.09), Gp4G (Vrel = 0.3) and Gp5G (Vrel = 0.33). An NMP is always one of the products. 3. 3. The Km values for Ap3 and Gp3G are 15 and 10μM respectively. 4. 4. Mg2+, Mn2+ and Ca2+ ions all stimulate the activity, while Zn2+, Co2+ and Ni2+ ions are inhibitory. 5. 5. The activity of the Np3Nase remains constant during pre-emergence development of encysted embryos but decreases slightly after hatching.

Original languageEnglish
Pages (from-to)565-571
Number of pages7
JournalInternational Journal of Biochemistry
Issue number4
Publication statusPublished - Apr 1992
Externally publishedYes

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