[The blocking effect of aliphatic hydrocarbons on Ca2+ leakage channels formed by aggregates of Ca2+-ATPase of the sarcoplasmic reticulum].
The effects of aliphatic hydrocarbons within the liposomes on the Ca2+ transport function of isolated sarcoplasmic reticulum (SR) membranes of rabbit skeletal muscle, vesiculate preparation of Ca2+ dependent ATPase and proteoliposomes reconstituted from Ca2+-ATPase and egg phosphatidylcholine, were studied. It was shown that liposomes prepared from dipalmitoyl phosphatidylcholine containing aliphatic hydrocarbons increase 2 to 3 times Ca2+ accumulation by Ca2+-dependent ATPase from rabbit skeletal muscle SR. Ca2+ transport by SR vesicles increases in the presence of hydrocarbons by 15--20%. The activating effect of hydrocarbons on Ca2+ transport by proteoliposomes depends on the lipid/protein ratio. The proteoliposomes with a high lipid/protein ratio are practically insensitive to the effects of hydrocarbons. It was suggested that activation of Ca2+ transport by hydrocarbons is due to blocking of Ca2+ leakage channels formed during the aggregation of Ca2+-ATPase molecules. Treatment of membranes by formaldehyde results in the oligomerization of Ca2+-ATPase and decreases 2--4-fold the ATP-dependent accumulation of Ca2+. Subsequent addition of decane restores Ca2+ transport practically completely.
Shevchenko
S I
SI
Chernova
T L
TL
Men'shikova
E V
EV
Ritov
V B
VB
D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000187:drug effects*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002751:Chlortetracycline / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D006838:Hydrocarbons / Q000494:pharmacology*; D007700:Kinetics; D009132:Muscles / Q000201:enzymology; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
D015220:Calcium Channels; D006838:Hydrocarbons; D000252:Calcium-Transporting ATPases; D002118:Calcium; D002751:Chlortetracycline
Blokiruiushchee deĭstvie alifaticheskikh uglevodorodov na kanaly utechki Ca2+, formiruemye agregatami Ca2+-ATPasy sarkoplazmaticheskogo retikuluma.