 "M. tuberculosis" can also grow on the lipid cholesterol as a sole source of carbon, and genes involved in the cholesterol use pathway(s) have been validated as important during various stages of the infection lifecycle of "M. tuberculosis".Amino acids are either used to synthesize proteins and other biomolecules, or oxidized to urea and carbon dioxide as a source of energy.The oxidation pathway starts with the removal of the amino group by a transaminase.