Analytical Products

1. Product Introduction

Protein L binds to the variable region of the kappa light chain of antibodies without interfering with the antigen-binding site. It can be used in chromatography media to capture antibodies and antibody fragments. Due to the influence of solution conditions, pH, and other factors, Protein L inevitably leaches in trace amounts during the chromatographic process, leading to Protein L residues in antibody drug products. The Protein L ELISA Kit produced by our company (Enzyme-Linked Immunosorbent Assay) is a highly sensitive detection kit for Protein L residues. It accurately recognizes the ligand of Diamond Protein L affinity chromatography media produced and sold by our company, enabling sensitive and precise detection of Protein L ligand residues in various biologics purified using Diamond Protein L.

2. Detection Principle

This kit is based on a double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) to measure Protein L residues in samples. Samples containing Protein L are first diluted with the Sample Diluent provided in the kit, then boiled to dissociate Protein L from the sample antibodies. After centrifugation, the supernatant is transferred into a microplate pre-coated with polyclonal anti-Protein L capture antibodies. A second anti-Protein L detection antibody, directly conjugated to horseradish peroxidase (HRP), forms a solid-phase antibody–Protein L–enzyme-labeled antibody sandwich complex. Following two wash steps to remove all unbound reactants, the complex reacts with tetramethylbenzidine (TMB), changing color from colorless to blue, and finally turning yellow upon addition of Stop Solution. The intensity of the color is proportional to the amount of Protein L ligand present in the sample. Absorbance (OD value) is measured at 450 nm and 650 nm, and the OD value is positively correlated with the Protein L content in the sample.

3. Kit Components

4. Storage

Store at 2–8°C.

5. Ordering Information