CATALYTIC POLAROGRAPHIC CURRENTS IN THE NICKEL-GLUTATHIONE SYSTEM .3.CATALYTIC HYDROGEN PREWAVE

In Ni2+-containing buffer solution at pH about 7, glutathione (Glu) pr oduces a catalytic hydrogen prewave with the half-wave potential -1.26 V vs. S.C.F. Glu is, however, much less active than cysteine, owing t o the low stability of nickel complexes involving coordination via sul fhydryl and amide nitrogen. Additionaly, Glu forms complexes without c atalytic activity in which Ni2+ is attached to the terminal glutamyl r esidue. The equilibrium between active and inactive complexes results in some mechanistic features explained by the suggested reaction schem e.