Biosynthesis of castor oil: effect of polyamines on the acylation of lysophosphatidic acid at the sn-2 position with ricinoleic acid.

Polyamines with diamine structures of chain length longer than 3C were essential for the synthesis of phosphatidic acid (PA) from ricinoleoyl-CoA and lysophosphatidic acid (LPA) by the castor LPA acyltransferase reaction, suggesting that polyamines modulate enzyme affinity for the acyl-CoA substrate in vivo.