Binding of gold to bovine serum albumin using flameless atomic absorption

• Published in: Journal of pharmaceutical sciences 1980-05, Vol.69 (5), p.585-587
• Main Authors: Melethil, Srikumaran, Poklis, Alphonse, Sagar, Vidya A.
• Format: Article
• Language: English
• Subjects: Animals; Antiarthritis agents-gold; Antiarthritis agents—gold, effect of plasma protein and gold concentrations on gold binding, flameless atomic absorption determination of gold in biological fluids; Aspirin-effect of salicylic acid on binding of gold to bovine serum albumin; Aspirin—effect of salicylic acid on binding of gold to bovine serum albumin, flameless atomic absorption determination; Binding Sites; Cattle; Drug Interactions; effect of plasma protein and gold concentration on gold binding; effect of plasma protein and gold concentrations on gold binding; effect of salicylic acid on gold bound to albumin; flameless atomic absorption determination; flameless atomic absorption determination of gold in biological fluids; Gold - metabolism; Molecular Weight; Protein Binding; Protein binding-gold to bovine serum albumin; Protein binding—gold to bovine serum albumin, effect of plasma protein and gold concentration on gold binding, effect of salicylic acid on gold bound to albumin, flameless atomic absorption determination; Salicylates - metabolism; Salicylic acid-effect on gold bound to serum albumin; Salicylic acid—effect on gold bound to serum albumin, flameless atomic absorption determination; Serum Albumin, Bovine - metabolism; Spectrophotometry, Atomic - methods
• ISSN: 0022-3549; 1520-6017
• DOI: 10.1002/jps.2600690529

A graphite furnace atomic absorption spectrophotometric assay capable of accurately determining nanogram amounts of gold in biological fluids was developed. The presence of bovine serum albumin and/or phosphate in the sample reduced the method sensitivity without affecting the linear response. Binding of gold was studied by ultrafil-tration using cones with a molecular weight cutoff of 25,000. The binding of gold at various concentrations to 2 and 4% bovine serum albumin in 0.1 M, phosphate buffer, pH 7.4, was independent of the gold and protein concentrations. In the 2–10-μg/ml range, the overall binding values (mean ± SD) of gold to 2 and 4% bovine serum albumin were 98 ± 1.6 (n = 35) and 99 ± 1.0% (n = 15), respectively. When ultrafiltration cones with a molecular weight cutoff of 50,000 were used, the extent of binding to 2% bovine serum albumin was 85.4 ± 1.6% (n = 11). This statistically significant difference (p < 0.001) was due to variations in the protein retention of the two cone types. Interaction studies showed that gold was not displaced from the binding sites by salicylic acid (200 μg/ml) or vice versa.