Linked Life Data

6326810

Source:http://linkedlifedata.com/resource/pubmed/id/6326810

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
1984-7-20
pubmed:abstractText
A cyclic nucleotide phosphodiesterase was extensively purified from the 100000g supernatant fraction of human platelets. The purification was 2500-3000-fold with 30% recovery of activity. The enzyme was isolated by DEAE-cellulose chromatography followed by adsorption to blue dextran-Sepharose and elution with cAMP. The protein has a molecular weight of 140 000 as determined by gel filtration. On NaDodSO4-containing polyacrylamide gels the major band is at 61 000 daltons, suggesting that the enzyme may exist as a dimer in solution under nondenaturing conditions. The enzyme requires Mg2+ or Mn2+ for activity. The calcium binding protein calmodulin does not stimulate hydrolysis of cAMP by this enzyme. The purified enzyme hydrolyzes both cAMP and cGMP with normal Michaelis-Menten kinetics with Km values of 0.18 microM and 0.02 microM, respectively. The hydrolysis of cGMP, however, is only one-tenth as rapid as the hydrolysis of cAMP. Cyclic GMP does not stimulate cAMP hydrolysis but instead is a potent competitive inhibitor of cAMP hydrolysis. The enzyme is also competitively inhibited by the phosphodiesterase inhibitors papaverine, 3-isobutyl-l-methylxanthine, and dipyridamole. The enzyme did not cross-react with an antibody raised to a cAMP phosphodiesterase isolated from dog kidney, indicating that the enzymes are not immunologically related. The inhibition of cAMP hydrolysis by cGMP suggests a possible regulatory link between these two cyclic nucleotides. One of the roles of cGMP in platelets may be to potentiate increases in intracellular cAMP by inhibiting the hydrolysis of cAMP by this enzyme.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
23
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1801-7
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1984
pubmed:articleTitle
Purification and characterization of a human platelet cyclic nucleotide phosphodiesterase.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't