Enzymatic synthesis, characterization, and metabolism of the coenzyme A ester of o-succinylbenzoic acid, an intermediate in menaquinone (vitamin K2) biosynthesis.

The enzymatic synthesis of the "active" o-succinylbenzoic acid is described and the factors controlling its formation are investigated. Tritium-labeled coenzyme A is incorporated into "active" o-succinylbenzoic acid, but label from [2-3H]ATP or [gamma-32P is not, indicating that the active compound is a coenzyme A thio ester(2). The compound is shown by two different methods to contain 1 mol only of coenzyme A per mol of o-succinylbenzoic acid. The o-succinylbenzoic and coenzyme A ester (2) is unstable at alkaline and neutral pH, but is fairly stable under acid conditions. The coenzyme A ester (2) is converted to 1,4-dihydroxy-2-naphthoic acid (3) by enzyme preparations from Mycobacterium phlei and Escherichia coli without any cofactor requirement.