2',3'-cyclic nucleotide 2'-phosphodiesterase from Fusarium culmorum.
We describe the properties of a 2',3'-cyclic nucleotide 2'-phosphodiesterase (EC 3.1.4.16), found in Fusarium culmorum, which hydrolyzes nucleoside 2',3'-cyclic monophosphates to nucleoside 3'-phosphates. In contrast with a similar enzyme found in bacteria, the Fusarium enzyme does not exhibit nucleotidase activity and does not show a requirement for metal ions, but is inhibited by micromolar concentrations of Cu++ and Zn++, and is very stable to heat. This cyclic phosphodiesterase hydrolyzes the four major nucleoside 2',3'-cyclic monophosphates and has greater affinity for purine (Kms for Ado-2',3'-P = 0.3 mM and for Guo-2',3'-P = 0.1 mM) than for pyrimidine nucleotides (Kms for Cyd-2',3'-P = 0.6 mM and for Urd-2',3'-P = 2 mM). The respective Vmax for Urd-2',3'-P; Cyd-2',3'-P; Ado-2',3'-P; and Guo-2',3' are 100:45:16:5. The efficacy of the phosphodiesterase to hydrolyze the four major 2',3' cyclic nucleotides (based on the relative values of Vmax/Km) is not significantly different. The Fusarium enzyme differs from a previously described 2',3' cyclic phosphodiesterase from Neurospora, in that it is inactive on 3',5'-nucleoside monophosphates and nucleoside 2' or 3' phosphates.
Fernández-Centeno
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Instituto de Investigaciones Biomédicas Alberto Sols, C.S.I.C. Facultad de Medicina, U.A.M. Arzobispo Morcillo 4, Madrid, Spain.
Heredia
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D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D001681:Biological Assay; D002412:Cations / Q000494:pharmacology; D002474:Cell-Free System; D017077:Culture Media, Conditioned; D010450:Endopeptidases / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004795:Enzyme Stability; D005670:Fusarium / Q000201:enzymology*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008670:Metals / Q000494:pharmacology; D013379:Substrate Specificity
D002412:Cations; D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors; D008670:Metals; D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases; D010450:Endopeptidases