In enzymology, a 4-methyleneglutaminase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are 4-methylene-L-glutamine and H<sub>2</sub>O, whereas its two products are 4-methylene-L-glutamate and NH<sub>3</sub>.
This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in linear amides. The systematic name of this enzyme class is 4-methylene-L-glutamine amidohydrolase. Other names in common use include 4-methyleneglutamine deamidase, and 4-methyleneglutamine amidohydrolase. This enzyme participates in c5-branched dibasic acid metabolism.