N-Methylglutamate Synthetase

N-methylglutamate synthetase (glutamate + methylamine ⇌ N-methylglutamate + ammonia) from Pseudomonas MA (ATCC 23819) has been purified and characterized. The purified enzyme exhibits multiple bands on disc gel electrophoresis; however, sedimentation equilibrium studies on the native enzyme, the succinylated enzyme, and the enzyme in 7 m guanidine hydrochloride all indicate homogeneity. In the presence of glutamate the enzyme has an s20,ω value of 13, while in the absence of glutamate dissociation of the enzyme into two components (s20,ω of 11 and 2.8) occurs. The native enzyme (molecular weight 350,000) is composed of approximately 12 subunits (molecular weight 30,000 to 35,000). The enzyme is specific for the amino acid substrate, but a number of amines can substitute for methylamine.