1.13.12.9 | crystals of noncatalytic proenzyme, activated enzyme, and enzyme o-amino benzoate complex, purified protein in 10 mM Tris-HCl (pH 8.0), concentrated, mixed with 0.1 M HEPES (pH 7.5) and 1.7 M ammonium sulfate (for the proenzyme) or 1.0 M ammonium sulfate (for the active enzyme), 30% glycerol in buffer as cryoprotectant, the enzyme amino benzoate complex is prepared by a soaking method with the cryoprotectant |