The development of protein purification techniques has always been an important issue over the decades. Affinity adsorption, one of the protein purification methods, is frequently used because of its binding specificity to the target compound. It could be applied to three different kinds of separations such as affinity adsorption, affinity precipitation, and affinity partition according to different requirements . Affinity adsorption is a novel separation method based on the specific binding of protein to the adsorbent. Three applications from the approach of affinity adsorption, classified by their bioselectivities, can be developed such as affinity ligands, immuno-affinity, and receptors. Affinity ligands may include enzyme substrates, enzyme inhibitors, dyes, heavy metal ions, and so forth. Starch, the substrate of α-amylase, either cross-linked or not, was used as one of the adsorbents for the isolation of amylases from wild strains or recombinant strains [2–4]. Various starch treatments can be applied such as adding ethanol or salt into amylase solution, and heat–moisture treatment, to enhance the adsorption of amylase . However, one major defect of applying starch material to the affinity adsorption is the easy hydrolysis of starch by the amylolytic enzyme mixture. Besides, it takes a longer time to reach adsorption equilibrium when compared with other polysaccharide materials. Alginate, a non-toxic and cheap polysaccharide of marine origin, was used to precipitate α-amylase from sweet potato with 80% activity yield and 44-fold purification . Agarose gel, a material often used in affinity chromatography, was activated by epichlorohydrin or bifunctional epoxides and was thus capable of binding with substances containing amino groups. Cyclohexaamylose (CHA) was used as the ligand.
The development of protein purification techniques has always been an important issue over the decades 几十年来，蛋白纯化技术的发展一直倍受关注。 Affinity adsorption, one of the protein purification methods, is frequently used because of its binding specificity to the target compound. 亲和吸附，蛋白纯化的一种方法，由于其与目标化合物的结合特异性而经常被使用。