Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1986-5-30
pubmed:abstractText
Coated microvesicles isolated from bovine neurohypophyses could be loaded with Ca2+ in two different ways, either by incubation in the presence of ATP or by imposition of an outwardly directed Na+ gradient. Na+, but not K+, was able to release Ca2+ accumulated by the coated microvesicles. These results suggest the existence of an ATP-dependent Ca2+-transport system as well as of a Na+/Ca2+ carrier in the membrane of coated microvesicles similar to that present in the membranes of secretory vesicles from the neurohypophysis. A kinetic analysis of transport indicates that the apparent Km for free Ca2+ of the ATP-dependent uptake was 0.8 microM. The average Vmax. was 2 nmol of Ca2+/5 min per mg of protein. The total capacity of microvesicles for Ca2+ uptake was 3.7 nmol/mg of protein. Both nifedipine (10 microM) and NH4Cl (50 mM) inhibited Ca2+ uptake. The ATPase activity in purified coated-microvesicles fractions from brain and neurohypophysis was characterized. Micromolar concentrations of Ca2+ in the presence of millimolar concentrations of Mg2+ did not change enzyme activity. Ionophores increasing the proton permeability across membranes activated the ATPase activity in preparations of coated microvesicles from brain as well as from the neurohypophysis. Thus the enzyme exhibits properties of a proton-transporting ATPase. This enzyme seems to be linked to the ion accumulation by coated microvesicles, although the precise coupling of the proton transport to Ca2+ and Na+ fluxes remains to be determined.
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-1054843, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-1177317, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-1255066, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-144139, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-159042, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-218020, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-2983664, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-4282706, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-4364656, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-492541, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-5432063, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-5970965, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-6131417, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-6131744, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-6142405, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-6142406, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-6146615, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-6219998, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-6225521, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-6298247, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-6370236, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-6413655, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-6450272, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-6712633, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-6770893, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-6814486, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-6838868, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-702106, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-7121829, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-7283132, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-7308482, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-7332540, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-7374963, http://linkedlifedata.com/resource/pubmed/commentcorrection/2939825-7412876
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0264-6021
pubmed:author
pubmed:issnType
Print
pubmed:day
1
pubmed:volume
233
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
643-8
pubmed:dateRevised
2009-11-18
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
Na+/Ca2+ exchange in coated microvesicles.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't