Detection of Non-Protein Components

Abstract

Within their natural biological environments, proteins often interact with other biological macromolecules, such as sugars, lipids, and nucleic acids. Sometimes these interactions are covalent, as in post-translational modifications of proteins, but more often involve non-covalent complex formation between the species. It is possible then, that non-protein com-ponents may occur in a protein sample, either as part of the biologically relevant active complex, or as contaminants that are not removed during purification. In this chapter we shall discuss methods for assessing the presence of the three most commonly occurring non-protein components in protein samples: nucleic acids, lipids from cell membranes, and covalently attached sugars in glycoproteins.