Threonine ammonia-lyase

In enzymology, a threonine ammonia-lyase is an enzyme that catalyzes the chemical reaction


 * L-threonine $$\rightleftharpoons$$ 2-oxobutanoate + NH3

Hence, this enzyme has one substrate, L-threonine, and two products, 2-oxobutanoate and NH3.

This enzyme belongs to the family of lyases, specifically ammonia lyases, which cleave carbon-nitrogen bonds. The systematic name of this enzyme class is L-threonine ammonia-lyase (2-oxobutanoate-forming). Other names in common use include threonine deaminase, L-serine dehydratase, serine deaminase, L-threonine dehydratase, threonine dehydrase, L-threonine deaminase, threonine dehydratase, L-threonine hydro-lyase (deaminating), and L-threonine ammonia-lyase. This enzyme participates in glycine, serine and threonine metabolism and valine, leucine and isoleucine biosynthesis. It employs one cofactor, pyridoxal phosphate.

Structural studies
As of late 2007, 4 structures have been solved for this class of enzymes, with PDB accession codes, , , and.