|Protein purification is a series of processes intended to isolate one or a few proteins from a complex mixture, usually cells, tissues or whole organisms. Protein purification is vital for the characterization of the function, structure and interactions of the protein of interest. The purification process may separate the protein and non-protein parts of the mixture, and finally separate the desired protein from all other proteins. Separation of one protein from all others is typically the most laborious aspect of protein purification. Separation steps usually exploit differences in protein size, physcio-chemical properties, binding affinity and biological activity.The top open access journals are peer reviewed scholarly journals of Enzyme Engineering. The top open access journals are freely available on the public internet domain, allowing any end users to read, download, copy, distribute, prink, search or link to the full texts of the articles. These provide high quality, meticulously reviewed and rapid publication, to cater the insistent need of scientific community. These journals are indexed with all their citations noted. The top open access journals are indexed in MEDLINE, PUBMED, SCOPUS, COPERNICUS, CAS, EBSCO and ISI.