L-3-cyanoalanine synthase

In enzymology, a L-3-cyanoalanine synthase (EC 4.4.1.9) is an enzyme that catalyzes the chemical reaction

L-cysteine + hydrogen cyanide L-3-cyanoalanine + hydrogen sulfide

Thus, the two substrates of this enzyme are L-cysteine and hydrogen cyanide, whereas its two products are L-3-cyanoalanine and hydrogen sulfide.

This enzyme belongs to the family of lyases, specifically the class of carbon-sulfur lyases. The systematic name of this enzyme class is L-cysteine hydrogen-sulfide-lyase (adding hydrogen cyanide L-3-cyanoalanine-forming). Other names in common use include beta-cyanoalanine synthase, beta-cyanoalanine synthetase, beta-cyano-L-alanine synthase, and L-cysteine hydrogen-sulfide-lyase (adding HCN). This enzyme participates in cyanoamino acid metabolism.

References

• Akopyan TN, Braunstein AE, Goryachenkova EV (1975). "Beta-cyanoalanine synthase: purification and characterization". Proc. Natl. Acad. Sci. U.S.A. 72 (4): 1617–21. doi:10.1073/pnas.72.4.1617. PMC 432590. PMID 1055433. 
• Castric PA, Conn EE (1971). "Formation of -cyanoalanine by O-acetylserine sulfhydrylase". J. Bacteriol. 108 (1): 132–6. PMC 247041. PMID 5001194. 
• Hendrickson HR (1968). "The beta-cyanoalanine synthase of blue lupine". Fed. Proc. 27: 593. 
• Hendrickson HR, Conn EE (1969). "Cyanide metabolism in higher plants. IV. Purification and properties of the beta-cyanolanine synthase of blue lupine". J. Biol. Chem. 244 (10): 2632–40. PMID 5769995.