In vitro penicillamine competition for protein-bound gold(I).
The reactions of penicillamine with gold sodium thiomalate (Myochrysine), gold-albumin complexes, and gold bound to urinary and kidney cytosolic proteins were examined. Large excesses of penicillamine (20 to 100:1 penicillamine/gold ratios) are required to mobilize significant amounts of protein bound gold. Quantitative comparisons of cysteine and penicillamine displacements of serum albumin bound gold indicate that penicillamine is approximately 5-6 times more effective than cysteine. Urinary gold is observed to be present in low molecular weight and protein bound forms, which exist in a labile chemical equilibrium and can be shifted by addition of penicillamine. These results are discussed in terms of the structure of gold(I)-penicillamine complexes and the distribution of gold(I) among protein and nonprotein thiol groups. The inappropriateness of using AuCl4- in vitro to study the biochemistry of chrysotherapy agents is delineated.
D000418:Albumins / Q000494:pharmacology; D000818:Animals; D001667:Binding, Competitive; D003600:Cytosol / Q000032:analysis; D006046:Gold / Q000652:urine; D006052:Gold Sodium Thiomalate / Q000494:pharmacology*; D007668:Kidney / Q000032:analysis; D008297:Male; D010396:Penicillamine / Q000494:pharmacology*; D011485:Protein Binding; D051381:Rats; D013438:Sulfhydryl Compounds / Q000494:pharmacology
D000418:Albumins; D013438:Sulfhydryl Compounds; D006052:Gold Sodium Thiomalate; D006046:Gold; D010396:Penicillamine