| pubmed-article:2935394 | rdf:type | pubmed:Citation | lld:pubmed |
| pubmed-article:2935394 | lifeskim:mentions | umls-concept:C0205054 | lld:lifeskim |
| pubmed-article:2935394 | lifeskim:mentions | umls-concept:C0005528 | lld:lifeskim |
| pubmed-article:2935394 | lifeskim:mentions | umls-concept:C1280500 | lld:lifeskim |
| pubmed-article:2935394 | lifeskim:mentions | umls-concept:C1979928 | lld:lifeskim |
| pubmed-article:2935394 | lifeskim:mentions | umls-concept:C0596235 | lld:lifeskim |
| pubmed-article:2935394 | lifeskim:mentions | umls-concept:C2346927 | lld:lifeskim |
| pubmed-article:2935394 | pubmed:issue | 2 | lld:pubmed |
| pubmed-article:2935394 | pubmed:dateCreated | 1986-3-12 | lld:pubmed |
| pubmed-article:2935394 | pubmed:abstractText | The ATP-dependent uptake of Ca2+ by rat liver microsomal fraction is dependent upon Mg2+. Studies of the Mg2+ requirement of the underlying microsomal Ca2+-ATPase have been hampered by the presence of a large basal Mg2+-ATPase activity. We have examined the effect of various Mg2+ concentrations on Mg2+-ATPase activity, Ca2+ uptake, Ca2+-ATPase activity and microsomal phosphoprotein formation. Both Mg2+-ATPase activity and Ca2+ uptake were markedly stimulated by increasing Mg2+ concentration. However, the Ca2+-ATPase activity, measured concomitantly with Ca2+ uptake, was apparently unaffected by changes in the Mg2+ concentration. In order to examine the apparent paradox of Mg2+ stimulation of Ca2+ uptake but not of Ca2+-ATPase activity, we examined the formation of the Ca2+-ATPase phosphoenzyme intermediate and formation of a Mg2+-dependent phosphoprotein, which we have proposed to be an attribute of the Mg2+-ATPase activity. We found that Ca2+ apparently inhibited formation of the Mg2+-dependent phosphoprotein both in the absence and presence of exogenous Mg2+. This suggests that Ca2+ may inhibit (at least partially) the Mg2+-ATPase activity. However, inclusion of the Ca2+ inhibition of Mg2+-ATPase activity in the calculation of Ca2+-ATPase activity reveals that this effect is insufficient to totally account for the stimulation of Ca2+ uptake by Mg2+. This suggests that Mg2+, in addition to stimulation of Ca2+-ATPase activity, may have a direct stimulatory effect on Ca2+ uptake in an as yet undefined fashion. In an effort to further examine the effect of Mg2+ on the microsomal Ca2+ transport system of rat liver, the interaction of this system with Sr2+ was examined. Sr2+ was sequestered into an A23187-releasable space in an ATP-dependent manner by rat liver microsomal fraction. The uptake of Sr2+ was similar to that of Ca2+ in terms of both rate and extent. A Sr2+-dependent ATPase activity was associated with the Sr2+ uptake. Sr2+ promoted formation of a phosphoprotein which was hydroxylamine-labile and base-labile. This phosphoprotein was indistinguishable from the Ca2+-dependent ATPase phosphoenzyme intermediate. Sr2+ uptake was markedly stimulated by exogenous Mg2+, but the Sr2+-dependent ATPase activity was unaffected by increasing Mg2+ concentrations. Sr2+ uptake and Sr2+-dependent ATPase activity were concomitantly inhibited by sodium vanadate. In contrast to Ca2+, Sr2+ had no effect on Mg2+-dependent phosphoprotein formation. Taken together, these data indicate that Mg2+ stimulated Ca2+ and Sr2+ transport by increasing the Ca2+ (Sr2+)/ATP ratio.(ABSTRACT TRUNCATED AT 400 WORDS) | lld:pubmed |
| pubmed-article:2935394 | pubmed:grant | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:2935394 | pubmed:language | eng | lld:pubmed |
| pubmed-article:2935394 | pubmed:journal | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:2935394 | pubmed:citationSubset | IM | lld:pubmed |
| pubmed-article:2935394 | pubmed:chemical | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:2935394 | pubmed:chemical | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:2935394 | pubmed:chemical | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:2935394 | pubmed:chemical | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:2935394 | pubmed:chemical | http://linkedlifedata.com/r... | lld:pubmed |
| pubmed-article:2935394 | pubmed:status | MEDLINE | lld:pubmed |
| pubmed-article:2935394 | pubmed:month | Jan | lld:pubmed |
| pubmed-article:2935394 | pubmed:issn | 0014-2956 | lld:pubmed |
| pubmed-article:2935394 | pubmed:author | pubmed-author:Kraus-Friedma... | lld:pubmed |
| pubmed-article:2935394 | pubmed:author | pubmed-author:FleschnerC... | lld:pubmed |
| pubmed-article:2935394 | pubmed:issnType | Print | lld:pubmed |
| pubmed-article:2935394 | pubmed:day | 15 | lld:pubmed |
| pubmed-article:2935394 | pubmed:volume | 154 | lld:pubmed |
| pubmed-article:2935394 | pubmed:owner | NLM | lld:pubmed |
| pubmed-article:2935394 | pubmed:authorsComplete | Y | lld:pubmed |
| pubmed-article:2935394 | pubmed:pagination | 313-20 | lld:pubmed |
| pubmed-article:2935394 | pubmed:dateRevised | 2007-11-14 | lld:pubmed |
| pubmed-article:2935394 | pubmed:meshHeading | pubmed-meshheading:2935394-... | lld:pubmed |
| pubmed-article:2935394 | pubmed:meshHeading | pubmed-meshheading:2935394-... | lld:pubmed |
| pubmed-article:2935394 | pubmed:meshHeading | pubmed-meshheading:2935394-... | lld:pubmed |
| pubmed-article:2935394 | pubmed:meshHeading | pubmed-meshheading:2935394-... | lld:pubmed |
| pubmed-article:2935394 | pubmed:meshHeading | pubmed-meshheading:2935394-... | lld:pubmed |
| pubmed-article:2935394 | pubmed:meshHeading | pubmed-meshheading:2935394-... | lld:pubmed |
| pubmed-article:2935394 | pubmed:meshHeading | pubmed-meshheading:2935394-... | lld:pubmed |
| pubmed-article:2935394 | pubmed:meshHeading | pubmed-meshheading:2935394-... | lld:pubmed |
| pubmed-article:2935394 | pubmed:meshHeading | pubmed-meshheading:2935394-... | lld:pubmed |
| pubmed-article:2935394 | pubmed:meshHeading | pubmed-meshheading:2935394-... | lld:pubmed |
| pubmed-article:2935394 | pubmed:meshHeading | pubmed-meshheading:2935394-... | lld:pubmed |
| pubmed-article:2935394 | pubmed:year | 1986 | lld:pubmed |
| pubmed-article:2935394 | pubmed:articleTitle | The effect of Mg2+ on hepatic microsomal Ca2+ and Sr2+ transport. | lld:pubmed |
| pubmed-article:2935394 | pubmed:publicationType | Journal Article | lld:pubmed |
| pubmed-article:2935394 | pubmed:publicationType | In Vitro | lld:pubmed |
| pubmed-article:2935394 | pubmed:publicationType | Research Support, U.S. Gov't, P.H.S. | lld:pubmed |
| pubmed-article:2935394 | pubmed:publicationType | Research Support, U.S. Gov't, Non-P.H.S. | lld:pubmed |
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| http://linkedlifedata.com/r... | pubmed:referesTo | pubmed-article:2935394 | lld:pubmed |
