The Studies on Brdicka's Catalytic Hydrogen-Wave l

Abstract

It is well known that the catalytic wave of protein discovered by Brdicka' shows a double wave in the solution of ammoniacal ammonium chloride containing either divalent or trivalent cobalt, and in general, the waves found with a trivalent cobalt solution are larger than those found with a divalent cobalt solution at the same total cobalt concentra tion. Brdicka2), in the series of his studies on the catalytic hydrogen wave, described that the wave was quite different in character when the ammoniacal solution contained divalent or trivalent cobalt. In order to learn more of the nature of the catalytic wave, a series of amino acids was tested, and he found that only cystine or cysteine showed a effect similar to protein in ammoniacal cobaltous solution, and that each of these compounds gave rise to a wave which was in the same position as the second wave of protein. The appearance of catalytic wave by cystine in the cobaltic solution was not described by him, and the difference of the catalytic wave in ammoniacal solution containing divalent or trivalent cobalt has not been known up to now.In 1954, Kalous and Ji.rsa discovered that during the polarographic investigation of cystine, the catalytic wave appeared even in the presence of trivalent cobalt in a solution of relatively high concentration, i.e., about 10-3M. Recently, he reported4) a complicated electrode reaction of influence of trivalent cobalt on the reduction of cystine and presented an explanation for the mechanism of the catalytic wave by using Kalousek commutatorn.In the present study, the catalytic wave of cystine with trivalent cobalt has been in vestigated by D.C. and A.C. polarograph to learn more of the electrode reactions. The parameters studied with respect to the effect on the catalytic wave were the concentration of cystine and cobalt and pressure of the dropping mercury electrode. A.C. polarographic waves showed the reduction waves corresponding to various D.C. polarographic waves given by cystine in the solution of ammoniacal trivalent cobalt. The relation between the reduction process of prewave of cystine (at -0.58 V.) and divalent cobalt at the surface of mercury produced by the reduction of trivalent cobalt, was investigated, and an explana tion for the mechanism of the catalytic wave was presented.