<p>This entry represents the enzyme O-succinylbenzoate-CoA ligase (MenE), which is involved in the fourth step of the menaquinone (vitamin K2) biosynthesis pathway. In bacteria, menaquinone is used during fumarate reduction in anaerobic respiration. In green sulphur bacteria and heliobacteria, menaquinones are thought to be used as a loosely bound secondary electron acceptor in the photosynthetic reaction centre. In cyanobacteria, the product of the menaquinone pathway is phylloquinone (2-methyl-3-phytyl-1,4-naphthoquinone), a molecule used exclusively as an electron transfer cofactor in Photosystem (PS) I [<cite idref="PUB00014943"/>].</p> O-succinylbenzoate-CoA ligase