Cystathionine

Cystathionine has a central role both in the biosynthesis of methionine in plants and bacteria and in the biosynthesis of cysteine in animals (Figure 21.8). In humans, deficiency of cystathionine synthase (Figure 21.9) leads to a condition called homocystinuria, in which homocysteine overaccumulates. The condition results in severe mental retardation and dislocation of the lens of the eye.

See also: Metabolism of Sulfur-Containing Amino Acids