These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Substrate and effector specificity of a guanosine 3':5'-monophosphate phosphodiesterase from rat liver.
    Author: Moss J, Manganiello VC, Vaughan M.
    Journal: J Biol Chem; 1977 Aug 10; 252(15):5211-5. PubMed ID: 195942.
    Abstract:
    Guanosine 3':5'-monophosphate phosphodiesterases, which appear to be under allosteric control, have been partially purified from rat liver supernatant and particulate fractions. The preferred substrate for both phosphodiesterases was cGMP (Km values: cGMP less than cIMP less than cAMP). At subsaturating concentrations of substrate, the phosphodiesterases were stimulated by purine cyclic nucleotides. The order of effectiveness for activation of cyclic nucleotide hydrolysis was cGMP greater than cIMP greater than cAMP greater than cXMP. Using cAMP derivatives as activators of cIMP hydrolysis, modifications in the ribose, cyclic phosphate, and purine moieties were shown to alter the ability of the cyclic nucleotide to activate the supernatant enzyme. cGMP, at concentrations that stimulated cyclic nucleotide hydrolysis, enhanced chymotryptic inactivation of the supernatant phosphodiesterase. At similar concentrations, cAMP was not effective. It appears that on interaction with appropriate cyclic nucleotides, this phosphodiesterase undergoes conformational changes that are associated with increased catalytic activity and enhanced susceptibility to proteolytic attack. Divalent cation may not be required for the nucleotide-phosphodiesterase interaction and resultant change in conformation.
    [Abstract] [Full Text] [Related] [New Search]