[Mechanism of the effect of EGTA on the affinity to calcium of Ca-transporting and Ca-binding cell systems].
The activity of Ca-ATPases of erythrocyte ghosts and sarcoplasmic reticulum and the rate of ATP-dependent uptake of 45Ca by erythrocyte membrane inside-out oriented vesicles, sarcoplasmic reticulum vesicles and mitochondria were investigated. It was found that in all cases studied the addition of EGTA to the incubation mixture caused an increase in the affinity of Ca-pumps for Ca2+; their maximal activity remained thereby unaffected. A similar effect of EGTA was observed when the affinity for Ca2+ of calmodulin, troponin C and the fluorescent dye quin 2 were determined. It was assumed that the effect of EGTA on the affinity for Ca2+ of Ca-transporting and Ca-binding systems of a cell is due to a removal of admixtures of bi- and trivalent cations.
Orlov
S N
SN
Sitozhevskiĭ
A V
AV
Pokudin
N I
NI
Agnaev
V M
VM
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism; D004533:Egtazic Acid / Q000494:pharmacology*; D004910:Erythrocyte Membrane / Q000201:enzymology / Q000378:metabolism; D005026:Ethylene Glycols / Q000494:pharmacology*; D005456:Fluorescent Dyes; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008930:Mitochondria, Liver / Q000201:enzymology / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D011921:Rats, Inbred WKY; D012519:Sarcoplasmic Reticulum / Q000201:enzymology / Q000378:metabolism; D014336:Troponin / Q000378:metabolism; D019209:Troponin C
D002135:Calcium-Binding Proteins; D002147:Calmodulin; D005026:Ethylene Glycols; D005456:Fluorescent Dyes; D014336:Troponin; D019209:Troponin C; D004533:Egtazic Acid; D000252:Calcium-Transporting ATPases; D002118:Calcium
O mekhanizme vliianiia EGTA na srodstvo k kal'tsiiu Ca-transportiruiushchikh i Ca-sviazyvaiushchikh sistem kletki.