Linked Life Data

6224790

Source:http://linkedlifedata.com/resource/pubmed/id/6224790

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
17
pubmed:dateCreated
1983-10-21
pubmed:abstractText
In isolated sarcoplasmic reticulum vesicles, calcium-chelating but non-calcium-precipitating dicarboxylates, such as maleate and succinate, stimulated ATP-dependent Ca2+ accumulation and its ensuring spontaneous Ca2+ accumulation and its ensuring spontaneous Ca2+ release, and Ca2+-dependent ATPase activity (Chu, A., Tate, C. A., Bick, R. J., Van Winkle, W. B., and Entman, M. L. (1983) J. Biol. Chem. 258, 1656-1664). We further examined the effect of dicarboxylates on enzyme turnover. The anionic buffer maleate enhanced the rate of rapid acyl phosphoenzyme hydrolysis compared to that in the zwitterionic buffer piperazine-N,N'-bis(2-ethanesulfonic acid) but had no effect on the phosphoenzyme formation. The presence of a calcium-precipitating anion, oxalate, or a Ca2+ ionophore, A23187, eliminated the differences observed in the phosphoenzyme decay between the two buffers, but accelerated the rate of decay. Furthermore, the catalytic activity of the purified Ca2+-dependent ATPase was not affected by maleate, whether oxalate was present or not. [14C]Succinate was transported into the sarcoplasmic reticulum in a manner which was dependent on Ca2+ transport, and occurred over a similar time course as Ca2+ accumulation/release. The net succinate uptake was equivalent to the amount of succinate-stimulated Ca2+ accumulation. Rapid efflux of both [14C]succinate and 45Ca2+ was induced by A23187, whereas the efflux induced by ethylene glycol bis(beta-aminoethylether)-N,N,N',N'-tetraacetic acid was slower and less compared to A23187. Succinate accumulation exhibited saturation kinetics with positive cooperativity (Km congruent to 20 mM; Hill coefficient = 1.70). When maleate and succinate were both present, they were equipotent, and had an additive stimulatory effect on peak 45Ca2+ accumulation at low concentrations. Maleate was a competitive inhibitor of succinate accumulation (Ki approximately equal to 17 mM; Hill coefficient = 1.75). KCl in the presence or absence of valinomycin did not influence succinate accumulation or release. The data suggest that succinate accumulation is Ca2+-dependent, but occurs at a saturable, divalent, anion-specific site. While this carrier or channel requires Ca2+ transport, it may be controlled by additional factors as well.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
258
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10543-50
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Anion effects on in vitro sarcoplasmic reticulum function. Co-transport of anions with calcium.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't