Linked Life Data

6282139

Source:http://linkedlifedata.com/resource/pubmed/id/6282139

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1982-7-8
pubmed:abstractText
Metal ions play important roles in the regulation of the activation of adenylate cyclase. Previous studies have suggested that an important site of action of metal ions is at or closely related to the nucleotide regulatory protein. The present studies examine the nature of the regulation of enzyme activity by divalent cations and the influence of Mn2+ on hormone binding and stimulation of adenylate cyclase. Studies were performed in canine renal cortical membranes. Substitution of Mg2+ by Mn2+ was associated with a progressive decline in the ability of GTP or PTH to stimulate adenylate cyclase activity. Mn2+ did not alter specific binding of an iodinated PTH analogue. However, in spite of the loss of guanine nucleotide stimulation of enzyme activity, the effects of guanine nucleotide on PTH binding were not altered in the presence of Mn2+. Substitution of Mg2+ by Mn2+ abolished the inhibitory effect of Ca2+ on basal adenylate cyclase activity. Similarly, the effects of GTP or PTH to enhance the inhibitory effects of Ca2+ on enzyme activity were abolished in the presence of Mn2+. Since Mg2+ and Ca2+ compete for a common allosteric site and Mn2+ abolished the effects of these cations, it would appear that Mn2+ also competes for the binding site of Mg2+ and Ca2+. The present studies demonstrating that Mn2+ does not affect hormone binding or the actions of guanine nucleotides on hormone binding yet totally eliminates the effect of GTP on enzyme activity indicate that the effect of Mn2+ occurs at the level of the interactions of the nucleotide regulatory component with the catalytic unit. In addition, these data suggest that there are two functionally distinct sites of guanine nucleotides with different ionic requirements.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
242
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
F457-62
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1982
pubmed:articleTitle
Regulation of PTH receptor-adenylate cyclase system of canine kidney: influence of Mn2+ on effects of Ca2+, PTH, and GTP.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't