Details

Autor(en) / Beteiligte

• Cao, Chengjing
• Lockwich, T
• Scott, T L
• Blumenthal, R
• Shamoo, A E

Titel

Uncoupling of Ca super(2+) transport from ATP hydrolysis activity of sarcoplasmic reticulum (Ca super(2+) + Mg super(2+))-ATPase

Ist Teil von

• Molecular and cellular biochemistry, 1991-01, Vol.103 (2), p.97-111

Erscheinungsjahr

1991

Quelle

SpringerLINK Contemporary (Konsortium Baden-Württemberg)

Beschreibungen/Notizen

• In reconstituted rabbit skeletal muscle (Ca super(2+) + Mg super(2+))-ATPase proteoliposomes, Ca super(2+)-uptake is decreased by more than 90% with T sub(2) cleavage (Arg-198). However, no difference in the ATP dependence of hydrolysis activity is seen between SR and trypsin-treated SR. A large decrease in E-P formation and hydrolysis activity of the enzyme appear only at T sub(3) cleavage, which represents the cleavage of A sub(1) fragment to A sub(1a)+ A sub(1b) forms. A theoretical model is developed in order to fit the extent of tryptic digestion of the A fragment of the (Ca super(2+) + Mg super(2+))-ATPase polypeptide with the loss of Ca super(2+)-transport. Fits of the theoretical equations to the data are consistent with that Ca super(2+)-transport system appears to require a dimer of the polypeptide (Ca super(2+) + Mg super(2+))-ATPase.