MetaCyc Enzyme: S-adenosyl-L-methionine:cinnamic acid carboxymethyltransferase

Species: Ocimum basilicum

Subunit composition of S-adenosyl-L-methionine:cinnamic acid carboxymethyltransferase = [MONOMER-10583]2

Molecular Weight of Polypeptide: 45 kD (experimental) [Qualley05]

Molecular Weight of Multimer: 88 kD (experimental) [Qualley05]

Gene-Reaction Schematic

Gene-Reaction Schematic

Enzymatic reaction of: S-adenosyl-L-methionine:cinnamic acid carboxymethyltransferase

Inferred from experiment

trans-cinnamate + S-adenosyl-L-methionine → methylcinnamate + S-adenosyl-L-homocysteine

The direction shown, i.e. which substrates are on the left and right sides, is in accordance with the direction in which it was curated.

The reaction is physiologically favored in the direction shown.

In Pathways: volatile cinnamoic ester biosynthesis

The gene(s) encoding for S-adenosyl-L-methionine:cinnamic acid carboxylmethyltransferase (CACMT) were identified in Ocimum basilicum using an EST database with genes known to have homology to carboxyl transferases such as benzoic acid methyltransferase (BAMT), salicylic acid methyltransferase (SAMT), and jasmonic acid methyltransferase (JMT). Three CACMT's have been found and one of them (CACMT1) was recombinant expressed in E. coli and characterized in vitro. It was demonstrated that the purified homodimeric CACMT1 expressed a high affinity towards cinnamic acid, whereas related enzymes like SAMT and BAMT could not use this compound as a substrate. Although the other substrates tested (benzoic acid and p-coumaric acid) had similar Km's the catalytic efficiency of CACMT1 (Kcat/Km) for those compounds was 10times and 80times lower than the one obtained for cinnamic acid [Qualley05].

Inhibitors (Unknown Mechanism): Cu2+ [Qualley05]Kinetic Parameters:
Substrate Km (μM) Citations
S-adenosyl-L-homocysteine 30.0 [Qualley05]
trans-cinnamate 60.0 [Qualley05]

pH(opt): 8.0 [Qualley05]


Qualley05: Qualley VA, Kapteyn J, Dudareva N, Gang DR, (2005) "Expression, purification, and characterization of a recombinant S-adenosyl-L-methionine: cinnamic acid carboxylmethyltransferase from sweet basil (Ocimum basilicum)." PSNA 2005 annual meeting, San Diego, personal communication.

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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