Purification of functional proteins facilitated by aptamer mediated affinity chromatography (AMAC)
19th September 2019
Purification of functional proteins is a key procedure in development and production of biologics and often relies on traditional ion exchange, hydrophobic interaction or size exclusion chromatography. Although these techniques are relatively gentle, obtaining the desired level of purity requires many sequential and sometimes repeated purification steps. Affinity separation is also frequently used method because it offers a high yield and purity due to very selective interaction of the target protein. However, the process typically requires fusion of the target protein with an affinity tag such as His or GST, which may alter protein conformation and thus change its physiochemical properties.
Antibodies are commonly used as capture probes in tag-less purification method, however they come with their own limitations such as lengthy development process, sensitive to temperature and also undergo denaturation over the time. Aptamers offer the best alternative to antibodies for a tag-free purification method as they are more stable and can be easily designed using our automated selection process under costumer-defined conditions to yield highly specific aptamers.
At Aptamer Group, we have developed a process that benefits the purification of untagged proteins in their active state using ‘aptamer mediated affinity chromatography’ (AMAC). The specificity of aptamers for their targets ensures that high levels of purity can be achieved from complex medium in a single AMAC step. Additionally the aptamers can be easily made with amine or thiol reactive groups to allow easy conjugation to the purification surface.
Protein loading, washing and elution steps are then carried out under customer-specified conditions. Mild elution conditions guarantee protein integrity following purification. In addition to these benefits, AMAC does not rely on affinity / solubility tags and therefore offers a simpler workflow for purifying ‘native’ proteins. Moreover, eluting under pre-determined conditions removes the need for harsh, denaturing reagents often required with other affinity ligands such as antibodies.