Affinity chromatography as it is known today, namely, the concept and the immense power of biorecognition as a means of purification, was introduced in 1968 by Cuatracasas, Wilchek, and Anfinsen (1). This technique is used in 60% of all purification protocols (2). Almost any given biomolecule that one wishes to purify has an inherent recognition site through which it recognizes a partner molecule. If one of these partners is immobilized on a polymeric carrier, it can be used to selectively capture the biomolecule of interest. Isolation of a protein by affinity chromatography is a very effective technique. It provides the protein in a pure state, enabling its identification by partial sequencing, either by mass spectrometry or by N-terminal microsequencing. Upon completion of the human genome project, a partial protein sequence is enough for retrieving its complete mRNA and hence its complete protein sequence.