FabULOUS Enzyme

The FabULOUS enzyme is supplied as a lyophilized powder with no preservatives added, and is available in 2000 unit vials for digestion of up to 2 mg IgG.

FabULOUS (SpeB) is a unique recombinantly produced cysteine protease that digests antibodies from many species and subclasses in the hinge region, producing a homogenous pool of Fab fragments. The enzyme requires reducing conditions for activity on IgG.

Detailed Information

FabULOUS (SpeB) is an enzyme for digestion of IgG in the hinge region. Human, mouse, rat, goat and sheep IgG are digested by FabULOUS, yielding Fab and Fc fragments. The primary digestion site on human IgG1 is ..KTHT / CPPCPAPE...

A digestion protocol at 37°C for one hour under reducing conditions is generally applicable. FabULOUS digests IgG in commonly used buffers with pH ranging from 6.5 to 8.0. FabULOUS requires a reducing agent in the digestion reaction and the reducing agent is likely to reduce interchain thiols.

The molecular weight of FabULOUS is 29 kDa and the enzyme contains a His-tag.

Storage and Stability

The FabULOUS enzyme is supplied lyophilized and is reconstituted by addition of water. After reconstitution, FabULOUS is stable for at least 1 month at +4-8°C. The product is shipped cold and should be stored at -20°C upon arrival.

Unit Definition

One unit digests ≥ 95% of 1 µg human IgG1 when incubated in PBS with 5 mM DTT or TCEP, pH 7.4 at 37°C for 1 hour.

Buffers and Reducing agents

FabULOUS digests IgG in commonly used buffers with pH ranging from 6.5 to 8.0 and best activity is obtained at 37°C. The enzyme requires reducing agent in the digestion reaction and depending on the reducing conditions, there is a chance that the interchain thiols will be reduced.

How to Order

For details on ordering please visit How to order. Click add to cart to buy online.


Please do not hesitate to contact us if you need a quotation or have inquiries on price of bulk quantities.



Product Specifications


Certificate of Analysis

FAQ and Support

Popular FAQ

FabULOUS enzyme reaction is inhibited with iodoacetamide, iodo acetic acid or lowering pH below 3.

Yes, FabULOUS requires reduced condition for activity and reaction is performed in the presence of 1-5 mM DTT or TCEP at neutral pH.

Yes, but a longer incubation time is needed.

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