Malate dehydrogenase (MDH) is an enzyme that plays a role in mycobacteria, including M. tb. MDH is involved in the oxidative tricarboxylic acid (TCA) cycle, which converts malate to oxaloacetate. M. tb utilize MDH to facilitate a reductive TCA cycle to produce fumarate for use as a terminal electron acceptor. This provides an alternative electron acceptor for M. tb in conditions of hypoxia.