Purification and characterization of Artemia 2',3'-cyclic nucleotide 3'-phosphodiesterase.
This paper describes the purification and properties of a 2',3'-cyclic nucleotide 3'-phosphodiesterase which hydrolyzes nucleoside 2',3'-cyclic monophosphates to nucleoside 2'-phosphates. The enzyme is present in encysted gastrulae of Artemia and its specific activity greatly increases during larval development. The purified enzyme has a molecular weight of around 55 000 as estimated by gel filtration, does not require metals for activity, is inhibited by Zn2+ and inactivated by Cu2+ and has a pH optimum at around neutrality. Based on the relative values of V(max)/Km, the specificity of the phosphodiesterase toward the four 2',3'-cyclic nucleotides is Guo-2',3'-P > Ado-2',3'-P > Cyd-2',3'-P > Urd-2',3'-P = 45:36:20:7. The enzyme from Artemia gastrulae is competitively inhibited by the four nucleosides 2'-phosphates (Ki values around 1 mM) while the enzyme from larvae is only inhibited by the purine nucleotides. The phosphodiesterase characterized in this work is more similar in substrate specificity to the 2',3'-cyclic nucleotide 3'-phosphodiesterase from the mammalian nervous system than to the plant enzyme. The functional relationship of this enzyme with the Artemia ribonuclease VI is discussed.
Díaz
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AR
Instituto de Investigaciones Biomédicas, C.S.I.C. Facultad de Medicina, U.A.M., Madrid, Spain.
Heredia
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CF
D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D000818:Animals; D001156:Artemia / Q000201:enzymology* / Q000254:growth & development; D003560:Cysts; D005775:Gastrula / Q000201:enzymology; D008970:Molecular Weight; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D013379:Substrate Specificity
D010726:Phosphodiesterase Inhibitors; D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases