Protein chemical modification is a problem-solving technique in research and technology. Modifications also occur in natural deteriorations. Generally these modifications are with the most reactive side chains and are predominantly oxidations, reductions, and nucleophilic and electrophilic substitutions. Deteriorations include peptide bond scissions, racemizations, β-eliminations, and formation of products by the reaction of proteins with added chemicals. Proteins are modified intentionally for structure-function relationship studies or for development of new and improved products. Although appearing quite varied, the techniques used in pharmacological, food and feed, or other industrial areas differ more operationally than from major differences in the levels of chemical sophistication that are used
