Studying protein–protein affinity and immobilized ligand–protein affinity interactions using MS-based methods

This review discusses the most important current methods employing mass spectrometry (MS) analysis for the study of protein affinity interactions. The methods are discussed in depth with particular reference to MS-based approaches for analyzing protein–protein and protein–immobilized ligand interactions, analyzed either directly or indirectly. First, we introduce MS methods for the study of intact protein complexes in the gas phase. Next, pull-down methods for affinity-based analysis of protein–protein and protein–immobilized ligand interactions are discussed. Presently, this field of research is often called interactomics or interaction proteomics. A slightly different approach that will be discussed, chemical proteomics, allows one to analyze selectivity profiles of ligands for multiple drug targets and off-targets. Additionally, of particular interest is the use of surface plasmon resonance technologies coupled with MS for the study of protein interactions. The review addresses the principle of each of the methods with a focus on recent developments and the applicability to lead compound generation in drug discovery as well as the elucidation of protein interactions involved in cellular processes. The review focuses on the analysis of bioaffinity interactions of proteins with other proteins and with ligands, where the proteins are considered as the bioactives analyzed by MS

Sample preparation for peptides and proteins in biological matrices prior to liquid chromatography and capillary zone electrophoresis

The determination of peptides and proteins in a biological matrix normally includes a sample-preparation step to obtain a sample that can be injected into a separation system in such a way that peptides and proteins of interest can be determined qualitatively and/or quantitatively. This can be a rather challenging, labourious and/or time-consuming process. The extract obtained after sample preparation is further separated using a compatible separation system. Liquid chromatography (LC) is the generally applied technique for this purpose, but capillary zone electrophoresis (CZE) is an alternative, providing fast, versatile and efficient separations. In this review, the recent developments in the combination of sample-preparation procedures with LC and CZE, for the determination of peptides and proteins, will be discussed. Emphasis will be on purification from and determination in complex biological matrices (plasma, cell lysates, etc.) of these compounds and little attention will be paid to the proteomics area. Additional focus will be put on sample-preparation conditions, which can be 'hard' or 'soft', and on selectivity issues. Selectivity issues will be addressed in combination with the used separation technique and a comparison between LC and CZE will be made. © Springer-Verlag 2005

CSR Disclosure Practices in the Zambia Mining Industry

The main objective of this chapter is to examine the corporate social responsibility (CSR) disclosure practices and the related motivation for (or lack thereof) CSR disclosures in the Zambian mining industry. Key CSR disclosures are examined to identify the trends in disclosure. Semi-structured interviews were also conducted with the mining managers to explore the underlying motives for such disclosures (non-disclosures) and the prospects that exist for future development. We find that there is very limited CSR disclosure by mining companies in Zambia, while CSR reporting is directed mainly towards ‘public image building’ and motivated by project financing purposes for those companies with a ‘western’ parent company. We argue that the lack of demand for such reporting from the Zambian citizenry has partly contributed to the low disclosures. Some international voluntary reporting guidelines have been adopted by ‘western’ parent mining companies, while reputation risk management remains a key concern for these companies. The study contributes to understanding the underlying motives for CSR disclosures in a developing country context