S-adenosyl-L-methionine:trans-caffeoyl-coenzyme A 3-O-methyltransferase from elicitor-treated parsley cell suspension cultures.
An S-adenosyl-L-methionine:caffeoyl-CoA 3-O-methyltransferase was purified 82-fold from elicitor-induced parsley cell suspension cultures by ammonium sulfate fractionation, anionic exchange and hydrophobic interaction chromatographies, and chromatofocusing. The enzyme has an apparent pI of 5.7 and a molecular weight of approx 48,000 determined by gel filtration chromatography. Maximal activity was observed at pH 7.5 in 50 mM phosphate or Tris-HCl buffers and the additional presence of 0.5 M NaCl. The methyltransferase activity was dependent on Mg2+, whereas EDTA, Mn2+, and Ca2+ inhibited the reaction. The partially purified enzyme efficiently catalyzed the methylation of caffeoyl-CoA, but also accepted with low affinity various other caffeic esters as substrates. Dark-grown parsley cells contained considerable methyltransferase activity which was nevertheless increased approx threefold within 12 h following the addition of a crude fungal elicitor to the cell suspensions. We propose that the O-methyltransferase activity is an important component in the rapid resistance response of the cells, which depends on the formation of cell wall-bound ferulic polymers.
Pakusch
A E
AE
Biologisches Institut II, Universität Freiburg, Federal Republic of Germany.
Kneusel
R E
RE
Matern
U
U
D000214:Acyl Coenzyme A / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology; D002478:Cells, Cultured; D002845:Chromatography; D002852:Chromatography, Ion Exchange; D004492:Edetic Acid / Q000494:pharmacology; D005590:Fractional Precipitation; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D008274:Magnesium / Q000494:pharmacology; D019684:Magnoliopsida; D008345:Manganese / Q000494:pharmacology; D008745:Methylation; D008780:Methyltransferases / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000378:metabolism; D008970:Molecular Weight; D010944:Plants / Q000201:enzymology*; D013379:Substrate Specificity
D000214:Acyl Coenzyme A; D008345:Manganese; C058645:caffeoyl-coenzyme A; D004492:Edetic Acid; D008780:Methyltransferases; C059825:caffeoyl-CoA O-methyltransferase; D008274:Magnesium; D002118:Calcium