Preconcentration of gold by Mimusops elengi seed proteins

The present study has been performed to preconcentrate gold using the proteins extracted from Mimusops elengi Linn. (Family: Sapotaceae) seed by radiometric technique using Au-198. Effects of buffer and pH dependence on the binding affinity of the gold have also been examined. It has been found that the binding of gold with M. elengi protein neither depends on the addition of buffer nor the composition (phosphate/citrate) of buffer. The adsorption of gold is also independent of pH of the solution. To verify the gold-protein interaction, inter-comparisons have been made between four different approaches, (1) notably extraction with anion-exchange resin Amberlite IRA 400, (2) trichloroacetic acid (TCA) precipitation, (3) isoelectric precipitation and (4) dialysis of protein after incubation with gold. Good agreement has been observed for all the cases. Binding of gold have been studied with three different concentrations of gold, 1, 10 and 50 ppm spiked with Au-198.