Tryptophan Oxygenase of Pseudomonas acidovorans

Abstract

Tryptophan oxygenase (L-tryptophan: oxygen oxidoreductase, EC 1.13.1.12)was purified to a state of homogeneity from substrate-induced Pseudomonas acidovorans.The sedimentation and diffusion coefficients of the homogeneous protein are SU),~, 6.26 x lo-l3 set, and DzO w, 4.78 X 10d7 cm2 set-l, and from these values a molecular weight, M,,D, of 121,000 is obtained.High and low speed equilibrium sedimentation experiments give molecular weights, Mesuii, of 118,000 and 123,000, respectively.Ammo acid analyses reveal no sulfur-containing amino acid residues other than methionine.Quantitative analytical data show 1 mole of ferriprotoporphyrin IX and only trace amounts of copper and nonheme iron per mole of holoenzyme.The major absorption bands in the optical spectrum of the native holoenzyme occur at 280 and 405 mp, and the specific absorbance values (EF~Z) are 1.20 and 1.88, respectively.Optical and electron paramagnetic resonance spectral data indicate that the single protoheme iron moiety of both the native (ferric) and the chemically reduced (ferrous) form of the holoenzyme exists predominantly in the high spin configuration.