LA-ICP-MS studies of zinc exchange by copper in bovine serum albumin using an isotopic enriched copper tracer

Abstract

In the present work the binding of Cu and Zn on bovine serum proteins was studied using a tracer experiment. One dimensional BN-PAGE gels with separated bovine serum proteins after gel electrophoresis were doped with an enriched isotope copper tracer (⁶⁵Cu) as a function of time (from 30 s up to 24 h). In several protein bands in 1D gel before tracer experiment metal ions (mostly Zn) were found by LA-ICP-MS. After experiments using enriched ⁶⁵Cu tracer ⁶⁵Cu/⁶³Cu isotope ratios with changed isotope ratio were measured by LA-ICP-MS. The isotope ratio measurements of copper by LA-ICP-MS as a function of time indicate a fast exchange of Zn bonded on bovine serum albumin. This experimental finding demonstrates the formation of copper-binding proteins during the tracer experiments in the 1D gel. It was attempted to identify the protein bands from bovine serum proteins separated by 1D gel electrophoresis by using biopolymer mass spectrometry with MALDI-TOF-MS after excision from the 1D gel and tryptic digestion.