Converts 2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate (SHCHC) to 2-succinylbenzoate (OSB) (PubMed:10194342, PubMed:8335646). Does not show detectable N-acylamino acid racemase (NAAAR) activity with N-acetyl-S-methionine as substrate (PubMed:10194342). (1R,6R)-6-hydroxy-2-succinyl-cyclohexa-2,4-diene-1-carboxylate = 2-succinylbenzoate + H2O kcat is 19 sec(-1) with SHCHC as substrate. Quinol/quinone metabolism; 1,4-dihydroxy-2-naphthoate biosynthesis; 1,4-dihydroxy-2-naphthoate from chorismate: step 4/7. Quinol/quinone metabolism; menaquinone biosynthesis. Belongs to the mandelate racemase/muconate lactonizing enzyme family. MenC type 1 subfamily.