Species: Galium mollugo
Protein extracts obtained from cell cultures of Galium mollugo mediate the conversion of 2-succinylbenzoate (OSB) to 4-(2'-carboxyphenyl)-4-oxobutyryl-CoA in the presence of CoA and ATP [Heide82].
Three CoA esters are generated under in vitro conditions, the mono-CoA ester 4-(2'-carboxyphenyl)-4-oxobutyryl CoA ("aliphatic" CoA, described in this pathway), the mono-CoA ester 2-(3'-carboxypropionyl)benzoyl CoA ("aromatic" CoA), and a di-CoA ester, 4-(2'-carboxyphenyl)-4-oxobutyryl-di-CoA. However, only the "aliphatic" CoA ester was further convertable to 1,4-dihydroxy-2-naphtoic acid (DHNA) by a microbial naphtoate synthase enzyme, indicating that this isomer is the true in vivo product [Kolkmann87].
Note that the authors have reported production of ADP, which is unlike the bacterial O-succinylbenzoate-CoA ligase, which forms AMP. However, while ADP was formed in large quantities, some AMP was formed as well, and thus the authors did not rule out that formation of AMP could also be catalysed by the ligase, which may be non-specific with respect to ATP hydrolysis.
The enzyme is highly substrate specific. Analogues of O-succinoylbenzoate such as O-malonylbenzoate, benzoylpropionate, benzoate, 2-acetylbenzoate and p-coumarate were not accepted.
Activity requires Mg2+. While Ca2+, Cu2+ and Zn2+ could not replace Mg2+, Ni2+ (85% compared to Mg2+), Mn2+ (75%) and Co2+ (66%) gave partial activity [Sieweke92].
Revised 08-Feb-2008 by Zhang P
Enzymatic reaction of: O-succinylbenzoate-CoA ligase
EC Number: 18.104.22.1682-succinylbenzoate + ATP + coenzyme A → 4-(2'-carboxyphenyl)-4-oxobutyryl-CoA + AMP + diphosphate
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.
T(opt): 28 °C [Sieweke92]
pH(opt): 6.8 [Sieweke92]
Heide82: Heide L, Kolkmann R, Arendt S, Leistner E (1982). "Enzymic synthesis of o-succinylbenzoyl-CoA in cell-free extracts of anthraquinone producing Galium mollugo L. cell suspension cultures." Plant Cell Reports, 1, 180-182.
Sieweke92: Sieweke, Hans-Jurgen, Leistner, Eckhard (1992). "O-succinylbenzoate: coenzyme A ligase from anthraquinone producing cell suspension cultures of Galium mollugo." Phytochemistry 31(7): 2329-2335.
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