Protein G, a cell surface protein of group G streptococci, is a Type III Fc receptor that binds to the Fc region of IgG by a non-immune mechanism similar to that of protein A from Staphylococcus aureus. This product contains three IgG binding domains, but its albumin-binding region has been removed. Additionally, His-tag and cysteine have been added to N- and C-termini, respectively, to facilitate purification and conjugation. This does not affect the protein's ability to bind to IgG.
Molecular Weight
29,000-35,000 Da was determined by SDS-PAGE while relative molecular mass calculated from amino acid sequence is ?24,000 Da.
Source
E. coli
Concentration
5 mg/ml before lyophilization
Bioactivity
The theoretical binding capacity is 3 mol IgG/mol protein G. Protein G is assayed using ELISA. The optimal concentration for coating plate is 5 ug/ml.
Synonyms
Protein G; G Protein
Purity
This product is chromatographically purified and shows predominantly a single band by SDS-PAGE.Focusing: pI of 4.69
Storage
This product is lyophilized in 1X PBS. It will remain stable at 4°C for several weeks. For longer periods, store it at -20°C.