Coumarins and Furanocoumarins

Elicitor‐induced biosynthesis of psoralens in Ammi majus L. suspension cultures

“…The model is consistent with the results of Tietjen et al [35], who showed first that the bulk of the coumarins induced in parsley suspension cultures accumulated in the culture fluid while the cell mass continued to increase. The model is supported by the observation that umbelliferone and its derivatives rather than its precursors accumulated in the culture fluid of induced Ammi majus [17] and Arracacia esculenta cell cultures (K. Harter and U. Matern, unpublished).…”

“…majus was confirmed to be far more active than that from either parsley or Arracacia In contrast to a previous report [28] The overall speed of marmesin formation is also held responsible for the fact that no demethylsuberosin could be recovered from elicitor-induced A . majus cell suspensions [17]. Furthermore, since the marmesin synthase was found to be associated with the prenyltransferase and the psoralen synthase activities in the endoplasmic reticulum, the entire synthesis of psoralens from umbelliferone appears to be sequentially catalyzed on membranes.…”

A novel multifunctional O -methyltransferase implicated in a dual methylation pathway associated with lignin biosynthesis in loblolly pine

“…The crude protein extracts from secondary developing xylem of loblolly pine (22) and yeast cells described above were used for enzyme assays with caffeic acid, 5-hydroxyferulic acid, or flavonoids as substrates as described (13), with the following modifications. Briefly, 50 l of reaction mixture contained 50 mM Tris⅐HCl (pH 7.5), 1 mM MgCl 2 , 4 nmol of phenolic substrate, 2 nmol of SAM- 14 Me, and 7-15 g of protein. Enzyme assays using caffeoyl CoA or 5-hydroxyferuloyl CoA were performed as described (16) with some modifications.…”

“…S-Adenosyl-L-methionine (SAM)- 14 Me, (0.56 mCi͞mmol; 1 Ci ϭ 37 GBq) was obtained from Amersham. Apigenin, chlorogenic acid, naringenin, and quercetin were obtained from Aldrich.…”

“…Although it has not been unambiguously proven at the molecular level because no gymnosperm OMT has been cloned, at the enzyme level, the concept of bifunctional CAOMT in angiosperms versus monofunctional OMT in gymnosperms has been widely accepted for the past 20 years (5). Overall, these OMTs use free hydroxycinnamic acids (5-7, 12, 13) as opposed to another class of angiosperm OMT, caffeoyl CoA 3-O-methyltransferase (CCoAOMT) (14)(15)(16) involved in lignin biosynthesis in Zinnia (17,18), which uses caffeoyl CoA and 5-hydroxyferuloyl CoA esters (17). At both nucleotide and predicted amino acid sequence levels, Zinnia CCoAOMT cDNA does not share any significant similarity with the cDNA encoding a Zinnia bifunctional CAOMT (18).…”