InterPro domain: IPR004433

MenD was thought to act as SHCHC synthase, but has recently been shown to act instead as SEPHCHC synthase. Conversion of SEPHCHC into SHCHC and pyruvate may occur spontaneously but is catalyzed efficiently, at least in some organisms, by MenH. 2-oxoglutarate decarboxylase/SHCHC synthase (menD) is a thiamine pyrophosphate enzyme involved in menaquinone biosynthesis [ 1 ].

1. Menaquinone biosynthesis in Escherichia coli: identification of 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylate as a novel intermediate and re-evaluation of MenD activity. Biochemistry 46, 10979-89