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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.Human, mouse, rat, goat and sheep IgG are digested by SpeB, yielding Fab and Fc fragments. The primary digestion site on human IgG1 is KTHT / CPPCPAPE.
Purified and homogenous Fab fragments can be used in many applications, including: 1. Study monovalent binding of Fab fragments to the antigen. 2. Elimination of Fc-mediated effector functions. 3. Reduced unspecific binding from Fc interactions.
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.
>40 U/μL
Less than 1.0 EU per μg by the LAL method / rFC method.
Supplied as 0.2 μm filtered solution in 20 mM Tris, 500 mM NaCl, pH7.0 with glycerol as protectant.
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This product is supplied and shipped on dry ice.