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Titolo:
INTERACTIONS OF VANADATE OLIGOMERS WITH SARCOPLASMIC-RETICULUM CA2-ATPASE()
Autore:
AURELIANO M; MADEIRA VMC;
Indirizzi:
UNIV COIMBRA,CTR BIOL CELULAR,DEPT ZOOL P-3049 COIMBRA PORTUGAL UNIV COIMBRA,DEPT BIOQUIM P-3049 COIMBRA PORTUGAL
Titolo Testata:
Biochimica et biophysica acta. Molecular cell research
fascicolo: 3, volume: 1221, anno: 1994,
pagine: 259 - 271
SICI:
0167-4889(1994)1221:3<259:IOVOWS>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
CALCIUM-TRANSPORT; SIMULTANEOUS BINDING; HIGH-AFFINITY; CA-2+-ATPASE; ATPASE; VANADIUM; V-51; NMR; PHOTOCLEAVAGE; DECAVANADATE;
Keywords:
ATPASE, CA2+-; SARCOPLASMIC RETICULUM; VANADATE OLIGOMER; (RABBIT SKELETAL MUSCLE);
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
44
Recensione:
Indirizzi per estratti:
Citazione:
M. Aureliano e V.M.C. Madeira, "INTERACTIONS OF VANADATE OLIGOMERS WITH SARCOPLASMIC-RETICULUM CA2-ATPASE()", Biochimica et biophysica acta. Molecular cell research, 1221(3), 1994, pp. 259-271

Abstract

Upon addition of sarcoplasmic reticulum (SR), the line width of tetrameric vanadate signal of V-51-NMR spectra narrowed in the presence of ATP and Ca2+, whereas monomeric vanadate line widths were broadened. Thus, ATP decreases the affinity of the enzyme for tetravanadate whereas it induces the interaction with monomeric vanadate. In the presence of Ca2+ it was observed that tetrameric and decameric vanadate bind toSR ATPase whereas monomeric vanadate only binds to SR when ATP is present. However, decameric vanadate clearly differs from vanadate oligomers present in monovanadate solutions in preventing the accumulation of Ca2+ by sarcoplasmic reticulum (SR) vesicles coupled to ATP hydrolysis. Mg2+ increased the inhibitory effect promoted by decavanadate whereas a slight enhancement of Ca2+ uptake was observed in the presence of monovanadate. For 5 mM Mg2+ a nominal 2 mM vanadium 'decavanadate' solution containing about 190 to 200 mu M decameric and less than 100 mu M monomeric species depressed the rate of Ca2+ uptake by 50% whereasa nominal 2 mM monovanadate solution containing about 662 mu M monomeric, 143 mu M dimeric and 252 mu M tetrameric species had no effect onthe rate of Ca2+ accumulation. However, 2 mM 'decavanadate' inhibits by 75% the SR Ca2+-ATPase activity whereas the presence of 2 mM 'monovanadate' produces an inhibitory effect below 50%. Therefore, the Ca:ATP stoichiometry of Ca2+ transport is enhanced by monovanadate. in the presence of oxalate, inhibition of SR Ca2+-ATPase activity by these solutions is enhanced to 97% and 86% whereas in the presence of the ionophore lasalocid, the inhibitory values were 87% and 19% for 2 mM decavanadate and 2 mM monovanadate solutions, respectively. Apparently, theincrease of vesicular Ca2+ concentration counteracts monovanadate inhibition of SR Ca2+-ATPase activity but it does not significantly affect decavanadate inhibition.

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Documento generato il 10/07/20 alle ore 18:03:21