Cloning and Expression of a Potato cDNA Encoding Hydroxycinnamoyl-CoA:TyramineN-(Hydroxycinnamoyl)transferase

• Published in: The Journal of biological chemistry Vol. 274; no. 7; pp. 4273 - 4280
• Main Authors: Schmidt, Axel, Grimm, Rudi, Schmidt, Jürgen, Scheel, Dierk, Strack, Dieter, Rosahl, Sabine
• Format: Journal Article
• Language: English
• Published: American Society for Biochemistry and Molecular Biology 01.02.1999
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.274.7.4273

Hydroxycinnamoyl-CoA:tyramine N -(hydroxycinnamoyl)transferase (THT; EC 2.3.1.110 ) catalyzes the transfer of hydroxycinnamic acids from the respective CoA esters to tyramine and other amines in the formation of N -(hydroxycinnamoyl)amines. Expression of THT is induced by Phytophthora infestans , the causative agent of late blight disease in potato. The amino acid sequences of nine endopeptidase LysC-liberated peptides from purified potato THT were determined. Using degenerate primers, a THT-specific fragment was obtained by reverse transcription-polymerase chain reaction, and THT cDNA clones were isolated from a library constructed from RNA of elicitor-treated potato cells. The open reading frame encoding a protein of 248 amino acids was expressed in Escherichia coli . Recombinant THT exhibited a broad substrate specificity, similar to that of native potato THT, accepting cinnamoyl-, 4-coumaroyl-, caffeoyl-, feruloyl- and sinapoyl-CoA as acyl donors and tyramine, octopamine, and noradrenalin as acceptors tested. Elicitor-induced THT transcript accumulation in cultured potato cells peaked 5 h after initiation of treatment, whereas enzyme activity was highest from 5 to 30 h after elicitation. In soil-grown potato plants, THT mRNA was most abundant in roots. Genomic Southern analyses indicate that, in potato, THT is encoded by a multigene family.