Which hydroxyl from either the phosphate or the glycerol is taken during synthesis of a phospholipid head?
In all phosphorylation reactions, the oxygen of the hydroxyl group in the substrate attacks P of phosphate. This is because of high partial positive charge on P which is bonded to four highly electronegative oxygen atoms. When the bond forms between the substrate oxygen atom and phosphorus of terminal phosphate, electrons are transferred to the O that bridges the ester bond between 2nd and 3rd phosphate. Therefore the O of the substrate is retained and that of the terminal phosphate (of ATP) becomes the part of the 2nd phosphate (now terminal phosphate of ADP).



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