Cystathionine beta synthase

Cystathionine beta synthase (CBS) is an enzyme that in humans is encoded by the CBS gene. CBS catalyzes the first step of the transsulfuration pathway, from homocysteine to cystathionine.

Function

Cystathionine beta synthase is a unique heme-containing enzyme that catalyzes a pyridoxal 5'-phosphate (PLP)-dependent condensation of serine and homocysteine to give cystathionine. This is the first step in the transsulfuration pathway, leading from homocysteine to cysteine.

Clinical significance

Defects in this gene are the cause of homocystinuria, an autosomal recessive disorder affecting multiple organ systems. Variations in the CBS gene can lead to disruptive enzyme activity, which can result in homocystinuria.

See also

• Homocystinuria
• Transsulfuration pathway
• Cysteine
• Serine
• Homocysteine

External links

• GeneCards