Properties of the red - violet complex of copper and penicillamine and further insight into its formation reaction.

A characteristic red-violet chromophore which forms in the reaction of cupric ion with beta-sulfhydryl- alpha-amino acids has been attributed by several authors to a mixed-valence Cu3L2 structure. We have isolated and examined the analogous chromophore of the chelating drug penicillamine (beta, beta-dimethyl-cysteine), finding instead a polymeric anion with a mixed valence Cu2L2 repeating unit. Direct evidence for a mixed valence polymer cooroborates earlier conclusions of Wilson and Martin (9). Under oxygen-free conditions the anionic complex forms in essentially quantitative yield according to the following reaction: (see article). It has been established that this reaction is halide ion-dependent. The chromophore may be isolated as a sodium salt. This form was found to be stable, and it possessed no measurable activity as an oxidation catalyst. It was also demonstrated through biological experiments with rabbits that a significant amount of the complex- (between 6 percent and 39 percent) is recovered in the urinary tract following intravenous infusions attaining between 1.8 and 10 ppm copper.