Oakland, California. 29 November 2012 – Rainin Instrument, a METTLER TOLEDO subsidiary, has published a new white paper describing the optimization of protein/antibody purification.
The paper, entitled “Optimizing Protein Purification Conditions,” highlights the use of Rainin PureSpeedTM Protein Tips. Using Rainin’s E4 XLS electronic pipette, PureSpeed tips allow for bidirectional sample flow over the purification resin bed, maximizing target protein capture by allowing the binding reaction to reach equilibrium. Potential concentration steps, which can actually degrade protein quality, are eliminated, saving time and costly rework.
To demonstrate the process, a 6-His-tagged protein and s 20 µL Ni-IMAC PureSpeed tips were used with a Rainin E4 XLS pipette. Back-and-forth capture flow was used to ensure complete resin exposure during all steps. Concentrations of imidazole in the wash buffer and final elution were varied to help illustrate purification optimization, targeting both quantity and purity of captured protein. The experiments illustrate that PureSpeed wash and elution chemistries, which are carried out at reduced volumes, generalize to larger scale preparative systems, making PureSpeed a cost-effective optimization tool.
The paper also reviews aspects such as protein size that can affect the capture equilibrium as well as ways to help enhance protein capture by adjusting pH and flow rate or increasing cycle numbers. Rainin’s ColorTrakTM Guide also proved useful at helping non-expert operators load and purify a specific protein or antibody.