The glyoxylate cycle, a variation of the tricarboxylic acid cycle, is an anabolic pathway occurring in plants, bacteria, protists, and fungi. The glyoxylate cycle centers on the conversion of acetyl-CoA to succinate for the synthesis of carbohydrates.
The glyoxylate cycle uses six of the eight enzymes associated with the tricarboxylic acid cycle: citrate synthase, aconitase, succinate dehydrogenase, fumarase, and malate dehydrogenase.
Citrate Synthase
4C to a 6C molecule
Aconitase
6C Citrate => 6C
6C cis-Aconitate => 6C
Succinate Dehydrogenase
=>
Fumarase
Fumarate =>
Malate dehydrogenase
L-Malate =>
The two cycles differ in that in the glyoxylate cycle, is converted into and by isocitrate lyase (ICL) instead of into α-ketoglutarate. This bypasses the decarboxylation steps that take place in the citric acid cycle, allowing simple carbon compounds to be used in the later synthesis of macromolecules, including glucose. Glyoxylate is subsequently combined with acetyl-CoA to produce malate, catalyzed by malate synthase. Malate is also formed in parallel from succinate by the action of succinate dehydrogenase and fumarase.
. The ternary complex contains malate, acetyl-CoA and Mg+2 ion[1].
