The role of cardiolipin as an acyl donor in dog heart N-acylethanolamine phospholipid biosynthesis.

N-Acylethanolamine phospholipids were produced from endogenous substrates with dog heart mitochondrial and microsomal preparations. With mitochondria the N-acyl group contained 13.8% linoleate, with microsomes only 3.6%. Cardiolipin comprised 18.5% of mitochondrial and 3.3% of microsomal lipid P and contained 93.7 and 72.4% linoleic acid, respectively. Incubation of dog heart subcellular fractions with [1-14C]linoleoyl cardiolipin in the presence of Ca2+ resulted in the formation of N-acylethanolamine phospholipids labeled primarily in the N-acyl and 1-O-acyl moieties. The data indicate that cardiolipin is the major source of linoleic acid used in the N-acylation of ethanolamine phospholipids by transacylase activity.