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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
3
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pubmed:dateCreated |
1985-5-23
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pubmed:abstractText |
Ca2+ transport across mammary-gland Golgi membranes was measured after centrifugation of the membrane vesicles through silicone oil. In the presence of 2.3 microM free Ca2+ the vesicles accumulated 5.8 nmol of Ca2+/mg of protein without added ATP, and this uptake was complete within 0.5 min. In the presence of 1 mM-ATP, Ca2+ was accumulated at a linear rate for 10 min after the precipitation of intravesicular Ca2+ with 10 mM-potassium oxalate. ATP-dependent Ca2+ uptake exhibited a Km of 0.14 microM for Ca2+ and a Vmax. of 3.1 nmol of Ca2+/min per mg of protein. Ca2+-dependent ATP hydrolysis exhibited a Km of 0.16 microM for Ca2+ and a Vmax. of 10.1 nmol of Pi/min per mg of protein. The stoichiometry between ATP-dependent Ca2+ uptake and Ca2+-stimulated ATPase varied between 0.3 and 0.7 over the range 0.03-8.6 microM-Ca2+. Both Ca2+ uptake and Ca2+-stimulated ATPase were strongly inhibited by orthovanadate, which suggests that the major mechanism by which Golgi vesicles accumulate Ca2+ is through the action of the Ca2+-stimulated ATPase. However, Ca2+ uptake was also decreased by the protonophore CCCP (carbonyl cyanide m-chlorophenylhydrazone), indicating that it may occur by other mechanisms too. The effect of CCCP may be related to the existence of transmembrane pH gradients (delta pH) in these vesicles: the addition of 30 microM-CCCP reduced delta pH from a control value of 1.06 to 0.73 pH unit. Golgi vesicles also possess a Ca2+-efflux pathway which operated at an initial rate of 0.5-0.57 nmol/min per mg of protein.
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-11772,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-122874,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-122934,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-13426112,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-14667,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-157714,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-204286,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-4098404,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-4286175,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-4309122,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-4452361,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-603028,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-6131893,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-6222732,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-6224489,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-6239617,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-6320801,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-649681,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-6654915,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-6743225,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-697758,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-7225423,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-7305960,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-7354039,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-7470073,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-932001,
http://linkedlifedata.com/resource/pubmed/commentcorrection/3157370-949345
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Mar
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pubmed:issn |
0264-6021
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
15
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pubmed:volume |
226
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
741-8
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pubmed:dateRevised |
2010-11-18
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pubmed:meshHeading |
pubmed-meshheading:3157370-Adenosine Triphosphate,
pubmed-meshheading:3157370-Animals,
pubmed-meshheading:3157370-Biological Transport,
pubmed-meshheading:3157370-Calcium,
pubmed-meshheading:3157370-Calcium-Transporting ATPases,
pubmed-meshheading:3157370-Female,
pubmed-meshheading:3157370-Golgi Apparatus,
pubmed-meshheading:3157370-Hydrogen-Ion Concentration,
pubmed-meshheading:3157370-Hydrolysis,
pubmed-meshheading:3157370-Intracellular Membranes,
pubmed-meshheading:3157370-Lactation,
pubmed-meshheading:3157370-Mammary Glands, Animal,
pubmed-meshheading:3157370-Pregnancy,
pubmed-meshheading:3157370-Rats,
pubmed-meshheading:3157370-Rats, Inbred Strains,
pubmed-meshheading:3157370-Time Factors
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pubmed:year |
1985
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pubmed:articleTitle |
Ca2+ transport and Ca2+-dependent ATP hydrolysis by Golgi vesicles from lactating rat mammary glands.
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pubmed:publicationType |
Journal Article,
In Vitro,
Research Support, Non-U.S. Gov't
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