Biosynthesis of very long chain fatty acids in microsomes from epidermal cells of Allium porrum L.

The elongation system present in leek epidermal cells functions to synthesize very long chain fatty acids which, in turn, are the precursors to alkanes. The elongation system is microsomal, employs only saturated acyl components of the endogenous lipid pool as acceptors, utilizes malonyl-CoA as the C2 donor, has an absolute requirement for ATP, and is markedly inhibited by acetyl-ACP. Only saturated acyl-CoAs are readily elongated to very long chain fatty acids by malonyl-CoA in the absence of ATP. ACP is not required by the microsomal system.