Involved in the TCA cycle. FumC seems to be a backup enzyme for FumA under conditions of iron limitation and oxidative stress (PubMed:7592392). Catalyzes the stereospecific interconversion of fumarate to L-malate (PubMed:1917897, PubMed:3282546). (S)-malate = fumarate + H2O Inhibited by ATP, citrate and S-2,3-dicarboxyaziridine. kcat is 1149 sec(-1) for fumarate (at pH 7.9). kcat is 595.2 sec(-1) for S-malate (at pH 7.9). Optimum pH is 8. Thermostable. Carbohydrate metabolism; tricarboxylic acid cycle; (S)-malate from fumarate: step 1/1. Homotetramer. Under conditions of iron limitation and oxidative stress. Cells lacking this gene show an increase of biofilm formation. There are 2 substrate-binding sites: the catalytic A site, and the non-catalytic B site that may play a role in the transfer of substrate or product between the active site and the solvent. Alternatively, the B site may bind allosteric effectors. Belongs to the class-II fumarase/aspartase family. Fumarase subfamily.