Mechanism of the ATP-dependent phosphatidylserine synthesis in liver subcellular fractions.
It has been shown that the ATP-dependent incorporation of [14C]serine into phosphatidylserine in rat liver mitochondrial and microsomal fractions is prevented by EGTA. On the other hand, at low (microM) Ca2+ concentrations, serine incorporation is strongly stimulated by ATP and Mg2+. This stimulatory effect is reduced by calcium ionophore A23187. It is therefore suggested that the ATP-dependent process is that of serine base-exchange reaction, stimulated by endogenous Ca2+ accumulated inside the microsomal vesicles by Ca2+,Mg2+-ATPase. The mitochondrial activity can be accounted for by contamination by the endoplasmic reticulum.
Barańska
J
J
Department of Cellular Biochemistry, Nencki Institute of Experimental Biology, Warszawa, Poland.
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology / Q000502:physiology; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D004533:Egtazic Acid / Q000494:pharmacology; D004721:Endoplasmic Reticulum / Q000378:metabolism; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D008930:Mitochondria, Liver / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D010718:Phosphatidylserines / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains; D012694:Serine / Q000378:metabolism
D010718:Phosphatidylserines; D000001:Calcimycin; D012694:Serine; D004533:Egtazic Acid; D000255:Adenosine Triphosphate; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D002118:Calcium