The enzyme hydroxyglutamate decarboxylase (EC 4.1.1.16) catalyzes the chemical reaction

3-hydroxy-L-glutamate 4-amino-3-hydroxybutanoate + CO₂

Hence, this enzyme has one substrate, 3-hydroxy-L-glutamate, and two products, 4-amino-3-hydroxybutanoate and CO₂.

This enzyme belongs to the family of lyases, specifically the carboxy-lyases, which cleave carbon-carbon bonds. The systematic name of this enzyme class is 3-hydroxy-L-glutamate 1-carboxy-lyase (4-amino-3-hydroxybutanoate-forming). This enzyme is also called 3-hydroxy-L-glutamate 1-carboxy-lyase. It employs one cofactor, pyridoxal phosphate.

• Umbreit WW, Heneage P (1953). "beta-Hydroxyglutamic acid decarboxylase". J. Biol. Chem. 201 (1): 15–20. doi:10.1016/S0021-9258(18)71344-6. PMID 13044771.