Chapter 7 Affinity chromatography

TL;DR: Affinity chromatography is a technique for the isolation of biologically active substances, making use of their exceptional property of selective and reversible binding of other substances, for which Reiner and Walch introduced the term “affinant.”

Abstract: Publisher Summary Affinity chromatography is a technique for the isolation of biologically active substances, making use of their exceptional property of selective and reversible binding of other substances, for which Reiner and Walch introduced the term “affinant.” An affinant can, therefore, be considered as a special case of a ligand. In alkaline medium, chymotrypsin and trypsin form a complex with the bound trypsin inhibitor, thus separating from the inactive material that passes through the column unretained. In general, any compound is suitable for the isolation of biologically active substances that bind it specifically, firmly, and reversibly. Because of the widely varying character of biologically active substances, chemically affinants are also of very diverse types and their classification is, therefore, based on their biochemical function rather than on their chemical structure. For proteins binding vitamins, the corresponding vitamin serves as the affinant—for example, biotin for the isolation of avidin.