Phenylalanine hydroxylase from Chromobacterium violaceum. Purification and characterization.

Phenylalanine hydroxylase was purified approximately 3000-fold to apparent homogeneity with a 13% yield and crystalized from L-phenylalanine-induced cells of Chromobacterium violaceum. The enzyme was shown to be composed of a single polypeptide chain with an estimated molecular weight of approximately 32,000. Some of the physical properties of the enzyme include: a Stokes radius of 26.0 A, a sedimentation coefficient of 2.71 S, a diffusion coefficient of 8.20 X 10(-7) CM2/S, a frictional ratio of 1.23, and an isoelectric point of pH 4.5. No detectable iron was found in the purified enzyme. Apparent Km values for L-phenylalanine and 2-amino-4-hydroxy-6,7-dimethyltetrahydropteridine were 140 and 54 muM, respectively.