Formation of ω-Feruloyloxypalmitic Acid and Tetradecyl Ferulate in Enzymic Extracts of Wound-Healing Potato Tuber Discs (Solanum tuberosum L.)

Abstract

Suberin is a complex heteropolyrmer comprizing lipidic components attached to a phenolic matrix [1]. It naturally covers the underground parts of plants but it is also synthesized at the surface of wound-healing plant tissues. While the composition and the biosynthesis of the fatty acids and alcohols components of suberin have been extensively studied, very little is known about the composition and the enzymology of the phenolic fraction [1,2]. Soluble ferulic acid esters of saturated fatty alcohols, ranging in carbon chain length from C₁₆ to C₂₈, have been isolated from suberized potato periderm and it has been postulated that these alkyl ferulates could be suberin monomers [2,3]. We recently reported [4] the occurence in suberizing potato periderm (Solanum tuberosum L. cv Bintje) of a wound-induced acyl-CoA transferase catalysing the formation of ferulic acid esters of several mediumchain 1-alkanols and also, very efficiently, of ω-hydroxypalmitic acid (Fig. 1). It is the first time that an enzyme (HHT= hydroxycinnamoyl-CoA: Ωhydroxypalmitic acid O-hydroxycinnamoyltransferase) conjugating lipids to hydroxycinnamic acids is characterized.