It has a Gibbs free energy value of zero kilojoules per mile under the conditions that we find in ourselves. Now, in step seven, this is a hydration step, and it's catalyzed by fumarase. And what fumarase does is it basically attaches a hydroxyl group from water onto this side, and the H ion is attached onto this side. And so we form the L isomer of malate. And once malate is formed, and this reaction releases negative 3.8 kilojoules per mole of energy. And once we form the malate, now the final enzyme, Malade dehydrogenase, is able to actually reduce the NAD plus into NADH, releasing an H plus ion.