[Several properties of the Ca-pump of rabbit skeletal muscle sarcoplasmic reticulum in hypercholesteremia].
Sarcoplasmic reticulum (SR) fragments from the skeletal muscles of rabbit with marked atherosclerosis possessed decreased Ca2+-accumulating capacity. Lowering of transport efficiency, namely reduction of the Ca/ATP ratio from 1.9--normal value--to 0.9 during the experiment at 26 degrees C was accompanied by activation of Ca-ATPase and simultaneously of the rate of Ca2+ outflux from the SR. Arrhenius plots of Ca-ATPase temperature dependence characterized under normal conditions by a break at 20--21 degrees C was linearized under hypercholesterolemia. At the same time there was a rise (from 0.03 under normal conditions to 0.15 in atherosclerosis) of cholesterol/protein ratio in the SR membrane preparations. Activation energy for Ca-ATPase crude membranes under normal conditions was equal to 15.6 and 28.7 kcal/mol above and below the break point respectively; this value for Ca-ATPase of membranes with increased cholesterol level was 19 kcal/mol for all the temperatures investigated.
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active; D002118:Calcium / Q000378:metabolism*; D006937:Hypercholesterolemia / Q000378:metabolism*; D008297:Male; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology / Q000378:metabolism*; D013816:Thermodynamics
D000251:Adenosine Triphosphatases; D002118:Calcium
Nekotorye svoĭstva Ca-nasosa sarkoplazmaticheskogo retikuluma skeletnykh myshts krolikov pri giperkholesterinemii.