For the gay village, see Malate, Manila.

Malate (O⁻OC-CH₂-CH(OH)-COO⁻) is the ionized form of malic acid. It is an important chemical compound in biochemistry. In the C4 carbon fixation process, malate is a source of CO₂ in the Calvin cycle.

In the citric acid cycle, (S)-malate is an intermediate formed by the addition of an -OH group on the si face of fumarate; it can also be formed from pyruvate via anaplerotic reactions. Malate dehydrogenase catalyzes the reversible conversion of malate into oxaloacetate using NAD as a cofactor.

Malate is also produced in guard cells of plant leaves. It is produced from starch. A build up of malate leads to a low water potential. Water then flows into the guard cells causing the stoma to open. The stomas don't necessarly open though.

Carboxylate anions | Cellular respiration