Stabilization of detergent-solubilized Ca2+-ATPase by poly(ethylene glycol).
The (Ca2+ + Mg2+)-ATPase from sarcoplasmic reticulum (SR) has been solubilized with 1-alkanoyl propanediol-3-phosphorylcholines with chainlengths ranging between 8 and 12 C atoms. A marked dependence of the ATPase activity upon the chainlength was found, indicating that alkyl chainlengths with 12 C atoms are necessary for retention of activity. Addition of poly(ethylene glycol) to the eluting buffers used for gel filtration of the ATPase-detergent micelles was found to increase the activity and the long-term stability significantly. In the presence of Ca2+, the elution volume indicated an ATPase dimer, whereas in the absence of Ca2+ the elution volume indicated a monomeric solution. The purity of the preparations after gel filtration was improved by subsequent chromatography with a hydroxyapatite column.
Welte
W
W
Institut für Biophysik und Strahlenbiologie der Universität Freiburg, F.R.G.
Leonhard
M
M
Diederichs
K
K
Weltzien
H U
HU
Restall
C
C
Hall
C
C
Chapman
D
D
D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000302:isolation & purification / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000302:isolation & purification / Q000378:metabolism*; D002845:Chromatography; D002850:Chromatography, Gel; D003902:Detergents; D004229:Dithiothreitol / Q000494:pharmacology; D017886:Durapatite; D004795:Enzyme Stability; D006882:Hydroxyapatites; D007700:Kinetics; D009132:Muscles / Q000201:enzymology*; D010713:Phosphatidylcholines; D011092:Polyethylene Glycols / Q000494:pharmacology*; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*; D012995:Solubility
D003902:Detergents; D006882:Hydroxyapatites; D010713:Phosphatidylcholines; D011092:Polyethylene Glycols; D017886:Durapatite; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D004229:Dithiothreitol