There are three basic steps in the methylcitrate cycle, as outlined below. Additionally, the mechanism is shown with its reactants, products, intermediates, and enzymes.
The major enzymes involved in this process are methylcitrate synthase (MCS) in step one, methylcitrate dehydratase (MCD) in step two, and 2-methylisocitrate lyase (MCL) in step three.
The PrpC gene, which encodes for enzyme methylcitrate synthase in the first step of the methylcitrate cycle, is the gene responsible for propionate metabolism in the process. Without this gene, the methylcitrate cycle and ultimate metabolism would not occur, but rather catabolism. The reaction of the methylcitrate cycle both overlaps and intertwines with the citric acid cycle and the glyoxylate cycle. Odd-chain fatty acids acetate and propionate are broken down by the β-oxidation cycle to form acetyl-CoA, which is further oxidized by the citric acid cycle, and propionyl-CoA, which is oxidized by the methylcitrate cycle. The substrate oxaloacetate is generated by the citric acid and glyoxylate cycles, and the product succinate is taken from the methylcitrate cycle to be used in the citric acid cycle.