A four-carbon dicarboxylic acid with the formula HOOCCH(OH)CH2
COOH. Malate is a TCA cycle intermediate. It is formed by hydration of fumarate and is oxidized to oxaloacetate with concomitant formation of NADH. Malate can also be formed from pyruvate by malic enzyme. Malate can be transported across certain membranes (see malate shuttle
). This is important in C4 plants, where malate is an intermediate in the Hatch-Slack pathway.