In enzymology, a malate dehydrogenase is an enzyme that catalyzes the chemical reaction below -malate + NAD+ ⇌ {\displaystyle \rightleftharpoons } pyruvate + CO2 + NADHThus, the two substrates of this enzyme are -malate and NAD+, whereas its 3 products are pyruvate, CO2, and NADH. Wikipedia