In enzymology, a formimidoylglutamate deiminase (EC 3.5.3.13) is an enzyme that catalyzes the chemical reaction

N-formimidoyl-L-glutamate + H₂O N-formyl-L-glutamate + NH₃

Thus, the two substrates of this enzyme are N-formimidoyl-L-glutamate and H₂O, whereas its two products are N-formyl-L-glutamate and NH₃.

This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in linear amidines. The systematic name of this enzyme class is N-formimidoyl-L-glutamate iminohydrolase. Other names in common use include formiminoglutamate deiminase, and formiminoglutamic iminohydrolase. This enzyme participates in histidine metabolism.

• Wickner RB, Tabor H (1971). N-Formimino-L-glutamate iminohydrolase (Pseudomonas sp.). Methods Enzymol. Vol. 17B. pp. 80–84. doi:10.1016/0076-6879(71)17012-7.