4-(2'-Carboxyphenyl)-4-oxobutyryl coenzyme A ester, an intermediate in vitamin K2 (menaquinone) biosynthesis.

Enzyme preparations from Mycobacterium phlei, Escherichia coli and Galium mollugo cell suspension cultures were incubated in the presence of 4-(2'-carboxyphenyl)-4-oxobutyrate (i.e. o-succinylbenzoic acid, OSB, 1), ATP, coenzyme A and Mg2+. The main product isolated from the incubation mixture was 4-(2'-carboxyphenyl)-4-oxobutyryl coenzyme A ester (2) as determined by comparison with synthetic coenzyme A esters. Synthetic and enzymically formed 4-(2'-carboxyphenyl)-4-oxobutyryl coenzyme A ester (2) was shown to be enzymically converted to an intermediate in vitamin K2 biosynthesis viz. 1,4-dihydroxy-2-naphthoic acid (5). The enzymic formation of 2-(3'-Carboxypropionyl)benzoyl coenzyme A ester (3) and 4-(2'-carboxyphenyl)-4-oxobutyryl-di-coenzyme A ester (4) was also observed. They appeared in minor amounts, however. These esters were not convertible to 1,4-dihydroxy-2-naphthoic acid (5).

Enzymic synthesis of o-succinylbenzoyl-CoA in cell-free extracts of anthraquinone producing Galium mollugo L. cell suspension cultures.

o-Succinylbenzoic acid (OSB) is an intermediate in the biosynthesis of shikimatederived anthraquinones. The cell free activation of o-succinylbenzoic acid in extracts of anthraquinone producing cells of Galium mollugo L. is demonstrated for the first time. This activation depends on the presence of ATP, coenzyme A and Mg(2+). The o-succinylbenzoic acid coenzyme A ester was identified by converting it to 1,4-dihydroxy-2-naphthoic acid by a bacterial enzyme, viz. naphthoatesynthase. It is thus demonstrated that the o-succinylbenzoic acid coenzyme A ester derived from bacteria and from Galium mollugo cells are identical.