The Purification and Characterization of L-Histidine Ammonia-lyase (Pseudomonas)

Histidineammonia-lyase was purified from a pseudomonad grown on L-histidine.Enzyme preparations appeared homogeneous in the ultracentrifuge and by analytical disc electrophoresis.Native enzyme had an s&,,~ of 11.1 S and a D2~,w of 0.50 X low6 cm2 see-l.A molecular weight of 214,000 was obtained from sedimentation velocity and diffusion and 211,000 from sedimentation equilibrium.The enzyme was dissociated by 6 M guanidine hydrochloride-O.1 M mercaptoethanol into subunits of molecular weight 35,000.Mercaptoethanol both activates and inhibits the native enzyme.