Cytidine 3':5'-monophosphate phosphodiesterase in mammalian tissues. Occurrence and biological involvement

J. F. Kuo, N. L. Brackett, M. Shoji, J. Tse

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


A phosphodiesterase activity that preferentially hydrolyzed cytidine 3':5'-monophosphate was partially purified from rat liver extract. The enzyme was best activated by Fe2+ (5 to 10 mM). Mn2+ and Mg2+ were less effective, whereas Zn2+, Co2+, and Ca2+ were ineffective. It exhibited kinetics typical of a high Km phosphodiesterase, with a Km for cyclic CMP of 2.4 mM. The enzyme, inhibited by theophylline and 1-methyl-3-isobutyl xanthine to much less extents than cyclic AMP and cyclic GMP phosphodiesterases, was found in all rat tissues examined, with highest levels seen in the liver, kidney, and intestine, and lowest levels found in the skeletal muscle, cerebellum, aorta, and blood cells. The enzyme levels in the regenerating liver were found to be about 40% lower than the control liver of rats; they were also 3 to 10 times lower in the fetal liver, lung, and heart than the corresponding adult tissues of guinea pigs. These findings suggest that depressed cyclic CMP phosphodiesterase may be in part related to cell proliferation, in line with reports that the regenerating liver has higher levels of cyclic CMP and cytidylate cyclase.

Original languageEnglish (US)
Pages (from-to)2518-2521
Number of pages4
JournalJournal of Biological Chemistry
Issue number8
StatePublished - 1978
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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