ResDetect™ Protein L ELISA Kit

Protein L was isolated from the surface of bacterial species Peptostreptococcus magnus and was found to bind Ig(IgG,IgM,IgA,IgE and IgD) through L chain interaction, from which the name was suggested. Despite this wide-ranging binding capability with respect to Ig classes, Protein L is not a universal immunoglobilin-binding protein. Binding of Protein L to immunoglobulins is restricted to those containing kappa light chains (i.e., k chain of the VL domain). In humans and mice, kappa (k) light chains predominate. The remaining immunoglobulins have lambda (l) light chains. The recombinant protein contains four immunoglobulin (Ig) binding domains (Bdomains) of the native protein. Besides antibody, protein L is also suitable for binding of a wide range of antibody fragments such as Fabs, single-chain variable fragments (scFv), and domain antibodies (Dabs).

The kit is developed for the detection of natural or structurally conserved recombinant forms of Protein L and a recombinant form of Protein L with very significant structural differences from natural Protein A such as MabSelectTM VL in Bioprocess manufacturing applications. It is used as a tool to aid in optimal purification process development and in routine quality control of in-process streams as well as final product .

1. Unopened kit should be stored at 2°C-8°C upon receiving. 2. Find the expiration date on the outside packaging and do not use reagents past their expiration date. 3. The opened kit should be stored per components table. The shelf life is 30 days from the date of opening.

The resDetect™ Protein L ELISA Kit is used to measure the levels of recombinant Protein L by employing a standard sandwich-ELISA format. The micro-plate in the kit has been pre-coated with anti- Protein L polyclonal antibody. Firstly, the standard samples provided in kit and your samples are treated with Denaturation Buffer to dissociation of Protein L and antibody, stand a few minute. Before adding standards and samples, add the Biotin-Anti- Protein L Antibody to the plate to ensure that the standard samples are neutralized by the Biotin-Anti- Protein L Antibody buffer solution and protect the pre-coated antibody on the plate. Then, add the standard samples and your samples to the plate and form Antibody-antigen (Protein L) - biotinylated antibody complex, incubate and wash the wells. Next add Horseradish peroxidase conjugated streptavidin (Streptavidin-HRP) to the plate, incubate and wash the wells to remove any unbound reactants. At last, load the tetramethylbenzidine (TMB) substrate into the wells and monitor a blue color. The reaction is stopped by the addition of a stop solution and the color turns yellow. The intensity of the absorbance can be measured at 450nm and 630nm on a microtiter plate reader. The OD Value reflects the amount of Protein L.