Sinapoyl malate

Cinnamic esters are also found as sugar esters, or as esters of a variety of other organic acids. For example, sinapoyl esters represent a class of UV-absorbing compounds in the family of the Brassicaceae. Examples include sinapoyl malate (1.19) present in leaves, and sinapoyl choline (1.20) present in roots (Ruegger and Chappie, 2001). 

Sinapoyl esters are phenolic compounds found in members of the Brassicaceae, which includes the model plant Arabidopsis thaliana. The two major sinapoyl esters are sinapoyl malate (3.92) and sinapoyl choline (3.93), which accumulate in leaves and seeds, respectively. Sinapoylmalate plays a role in the protection against UV-radiation (Landry et al., 1995), whereas sinapoyl choline may be used as a storage form of choline in seeds (Shirley and Chappie, 2003). The precursor of these two esters is sinapate (3.35). 

Do, G.T., Pollet, B., Thevenin, ]., Sibout, R., Denoue, D., Barriere, Y., Lapierre, C. and Jouanin, L. (2007) Both caffeoyl coenzyme A 3-O-methyltransferase 1 and caffeic acid O-methyltransferase 1 are involved in redundant functions for lignin, flavonoids and sinapoyl malate biosynthesis in Arabidopsis. Planta, 226,1117-29. 

Later, an Arabidopsis fahl mutant was obtained which lacked sinapoyl malate (90) that is constitutively present in WT lines. This was considered to result from a deficiency in F5H activity,with the putative F5H gene (designated CYP84A1) subsequently obtained by T-DNA tagging. It encoded an enzyme of molecular... 

Isolation of a cDNA encoding an SCPL protein responsible for the synthesis of glucose polyesters has been reported [120], These compounds are produced in trichomes of Lycopers icon pen-nellii and Solanum berthaultii as a defense against insect attack. An SCPL enzyme responsible for the formation of UV-protecting sinapoyl malate in leaves of the Brassicaceae has also been described [121]. 

Figure 3-13. Sinapoyl ester metabolism catalyzed by the enzymes (a) UDP-glucose sinapic acid glucosyltransferase (SGT), (b) sinapoylglucose malate sinapoyltransferase (SMT), (c) sinapoylglucosexholine sinapoyltransferase (SCT), and (d) sinapoylcholinesterase (SCE).

STRACK, D., Development of l-O-sinapoyl-p-D-glucose L-malate sinapoyltransferase activity in cotyledons of red raddish Raphanus salivas L. var. 

In germinating seeds, the choline esters are transformed into the corresponding malates. In young plants 2-O-sinapoyl-L-malic acid predominates (8-94), while the main depsides in older plants are 2-0-(4-coumaroyl)-L-malic acid and 2-O-cafleoyl-L-... 

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