Kinetic studies of ferrous ion oxidation with crystalline human ferroxidase (ceruloplasmin).
نویسنده
چکیده
The kinetics of the catalysis of Fe(I1) oxidation by crystalline human ferroxidase (ceruloplasmin) has been studied under various conditions at 30’. Two Km values with respect to Fe(U), Km1 = 0.6 /.tM and Km2 = 50 PM, were obtained at pH 6.5, at which ferroxidase gave the maximum activity of 550 Fe(I1) per ferroxidase per min in an acetate buffer. Competition between the two substrates, p-phenylenediamine and Fe(II), was observed. The stoichiometry of Fe(U), ferroxldase, and oxygen, determined from the experimental data, was 4: 1: 1.
منابع مشابه
Kinetic studies of ferrous ion oxidation with crystalline human ferroxidase. II. Rate constants at various steps and formation of a possible enzyme-substrate complex.
The reaction between crystalline human ferroxidase (ferro:On oxido-reductase, EC 1.12.3) and the substrate, Fe(H), was studied by a stop-flow method. The rate constants for four separate steps-enzyme-substrate complex formation, separation of product from the enzyme, reoxidation by molecular oxygen, and a rate-determining step-were estimated to be kl = 1.2 x lo6 M-I set-I, kp = 13 set-*, ka = 5...
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ورودعنوان ژورنال:
- The Journal of biological chemistry
دوره 241 21 شماره
صفحات -
تاریخ انتشار 1966