Flavonol 3‐O‐glycoside hydroxycinnamoyltransferases from Scots pine (Pinus sylvestris L.)

摘要: Flavonol 3-O-glucosides esterified with ferulic or p-coumaric acid at positions 3'' and 6'' are the major UV-B screening pigments of epidermal layer Scots pine (Pinus sylvestris) needles. The last steps in biosynthesis these compounds catalyzed by enzymes that transfer acyl part hydroxycinnamic CoA esters to flavonol 3-O-glucosides. A newly developed enzyme assay revealed three 3-O-glucoside hydroxycinnamoyltransferases (HCTs) needles specificities for 3'', 4'' 6''. groups were identified cochromatography reference NMR spectroscopy. characterized molecular mass, isoelectric point, also pH temperature optima. Substrate glycosides as well kinetic properties 3''- 6''HCT suggested acylation preferably occurs glucosides p-coumaroyl-CoA. In addition, takes place a well-defined order, beginning position followed 3''. These results give first detailed characterization 3-O-glycoside HCTs involved protection plant tissues against (280-315 nm) radiation.