The mechanism of malate synthase is a combination of a Claisen-Schmidt condensation and a hydrolysis of an acyl-CoA. Initially, the aspartic acid 631 acts as a catalytic base, abstracting a proton from the alpha carbon of acetyl-CoA and creating an enolate that is stabilized by Arginine 338. This is considered to be the rate-determining step of the mechanism. Then, the newly formed enolate acts as a nucleophile that attacks the aldehyde of the glyoxylate molecule, imparting a negative charge on the oxygen which is stabilized by the Arginine 338 and the coordinating magnesium cation. This malyl-CoA intermediate then undergoes hydrolysis at the acyl-CoA portion, replacing it with a carboxylate anion. The enzyme is free to release the malate and the coenzyme A molecules. The citric acid cycle (also known as the tricarboxylic acid cycle or the Krebs cycle) is used by aerobic organisms to produce energy via the oxidation of acetyl-CoA, which is derived from pyruvate (a product of glycolysis). The citric acid cycle accepts acetyl-CoA and metabolizes it to form carbon dioxide. A related cycle, called the glyoxylate cycle, is found in many bacteria and plants. In plants, the glyoxylate cycle takes place in glyoxysomes. In this cycle, isocitrate lyase and malate synthase skip over the decarboxylation steps of the citric acid cycle. In other words, malate synthase works together with isocitrate lyase in the glyoxylate cycle to bypass two oxidative steps of Krebs cycle and permit carbon incorporation from acetate or fatty acids in many microorganisms. Together, these two enzymes serve to produce succinate (which exits the cycle to be used for synthesis of sugars) and malate (which remains in the glyoxylate cycle). During this process, acetyl-CoA and water are used as substrates. As a result, the cell does not lose 2 molecules of carbon dioxide as it does in the Krebs cycle. The glyoxylate cycle, facilitated by malate synthase and isocitrate lyase, allows plants and bacteria to subsist on acetyl-CoA or other two carbon compounds. For example, "Euglena gracilis", a single-celled eukaryotic alga, consumes ethanol to form acetyl-CoA and subsequently, carbohydrates.