Reaction: (1) (E)-4-coumaroyl-CoA + 5-hydroxyanthranilate = avenanthramide A + CoA
(2) (E)-caffeoyl-CoA + 5-hydroxyanthranilate = avenanthramide C + CoA
Glossary: avenanthramide A = 5-hydroxy-2-[(2E)-3-(4-hydroxyphenyl)prop-2-enamido]benzoate
avenanthramide C = 2-[(2E)-3-(3,4-dihydroxyphenyl)prop-2-enamido]-5-hydroxybenzoate
Other name(s): HHT1 (gene name); HHT4 (gene name)
Systematic name: hydroxycinnamoyl-CoA:5-hydroxyanthranilate N-hydroxycinnamoyltransferase
Comments: The enzyme participates in the biosynthesis of avenanthramides, phenolic alkaloids found mainly in oats (Avena sativa). It is related to EC 22.214.171.124, shikimate O-hydroxycinnamoyltransferase. The enzyme from oat does not accept feruloyl-CoA as a substrate.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
1. Ishihara, A., Matsukawa, T., Miyagawa, H., Ueno, T. and Mayama, S. Induction of hydroxycinnamoyl-CoA: hydroxyanthranilate N-hydroxycinnamoyltransferase (HHT) activity in oat leaves by victorin C. Z. Naturforsch. C 52 (1997) 756-760.
2. Yang, Q., Trinh, H.X., Imai, S., Ishihara, A., Zhang, L., Nakayashiki, H., Tosa, Y. and Mayama, S. Analysis of the involvement of hydroxyanthranilate hydroxycinnamoyltransferase and caffeoyl-CoA 3-O-methyltransferase in phytoalexin biosynthesis in oat. Mol. Plant Microbe Interact. 17 (2004) 81-89. [PMID: 14714871]
3. D'Auria, J.C. Acyltransferases in plants: a good time to be BAHD. Curr. Opin. Plant Biol. 9 (2006) 331-340. [PMID: 16616872]
4. Bontpart, T., Cheynier, V., Ageorges, A. and Terrier, N. BAHD or SCPL acyltransferase? What a dilemma for acylation in the world of plant phenolic compounds. New Phytol. 208 (2015) 695-707. [PMID: 26053460]
5. Li, Z., Chen, Y., Meesapyodsuk, D. and Qiu, X. The biosynthetic pathway of major avenanthramides in oat. Metabolites 9 (2019) . [PMID: 31394723]