Can I use FabRICATOR Fab2 Kit for generation and purification of fragments from Rabbit IgG?

FabRICATOR Fab2 Kit digests rabbit IgG but to capture the Fc fragments in the affinity step you need another resin than the CaptureSelect™ Fc normally included in the kit. Please contact the Genovis team if you are interested in processing rabbit IgG and we will provide columns with resin compatible with rabbit Fc in the FabRICATOR Fab2 Kit.

Can I re-use FabRICATOR Immobilized columns?

We can only guarantee optimal digestion for one-time use. We do not have a cleaning or regeneration protocol to provide. However, depending on the antibody and the following application the column can be reused. We do not recommend using with different antibodies due to the risk for contamination of carry-over from previous sample. If column reuse is desired store the column in 10-20% ethanol at +4-8°C.

Can I release Fc fragments from the CaptureSelect column after isolating the F(ab’)2 fragments?

It is possible to elute the Fc fragments from the CaptureSelect column using a low pH buffer, for example a 0.1M Glycine buffer pH=3.0. The pH must immediately after elution be adjusted to neutral pH by adding 0.1x elution volume of 1M Tris pH=8.0.

Can I use protein A or MabSelectSure (GE) for removal of Fc-fragments?

Genovis has chosen CaptureSelect in the FabRICATOR Fab2 Kit for removal of Fc fragments. CaptureSelect has a very high specific affinity for the Fc. Both protein A and MabSelect Sure (GE) may have affinity for the Fab which may result in a lower recovery of the generated F(ab’)2 fragments and the degree of affinity is antibody dependent. We have many customer reports on this subject, and they usually come back to us for the CaptureSelect columns for the above reason.

Where does FabRICATOR cleave the IgG molecule?

FabRICATOR® cleave the IgG molecule in one specific site in the lower hinge region of the anitbody leaving a F(ab’)2 fragment and a Fc-fragment.
Human IgG1:  ..CPAPELLG / GPSVF..
Human IgG2:  ..CPAPPVA / GPSVF..
Human IgG3:  ..CPAPELLG / GPSVF..
Human IgG4:  ..CPAPEFLG / GPSVF..

Does FabRICATOR introduce modifications?

FabRICATOR is a cysteine protease. It should not result in any other modifications than the digestion of the peptide bond. Digestion will be between the two Glycines (…CPAPELLG / GPSVF…) and the C-terminus will regain the carboxyl group – that is addition of one OH-group and the N-terminal amino group will be regained (addition of one H).

In summary, R1-CO-NH-R2 + H2O –> R1-COOH + NH2-R2.