Recombinant Protein G conjugated to horseradish peroxidase, supplied as a stabilised 50% glycerol solution at 1 mg/mL, 1 mg. Protein G binds the Fc region of IgG from a broad range of mammalian species with high affinity, so a single HRP-labelled reagent replaces species-specific secondary antibodies in ELISA, Western blotting and dot blot. Recombinant in E. coli and affinity-purified, then gel-filtered to remove aggregates. A universal IgG-detection reagent that complements the immunoglobulin-binding reagent Protein A cat. 339.
SPECIFICATIONS
Catalogue number: 857 | Product: Protein G – HRP conjugate
Source: Protein G, recombinant in E. coli, affinity-purified
Conjugate: horseradish peroxidase (HRP)
Purification: gel filtration to remove protein aggregates
Format: solution containing 50% glycerol, 0.05 M sodium phosphate pH 7.5, bovine serum albumin 5 mg/mL and Protein G – HRP conjugate at 1 mg/mL
Reactivity (ELISA): human IgG 100%; rabbit IgG 100%; goat IgG 100%; mouse IgG 30%; human IgA <5%; human IgM <5%; human serum albumin <0.2%; bovine serum albumin <0.2%
Recommended dilution: ELISA 1:10 000
Package size: 1 mg
STORAGE
Shipped at ambient temperature.
Store 1 year at −20 °C. The 50% glycerol formulation does not freeze solid at −20 °C, so the vial can be used directly without thawing.
Avoid repeated freeze-thaw cycles.
APPLICATIONS
- ELISA — detection reagent for bound IgG, recommended dilution 1:10 000.
- Western blotting — HRP detection of primary IgG antibodies.
- Dot blot — rapid screening of IgG-containing fractions and hybridoma supernatants.
- Universal secondary reagent for human, rabbit and goat primary IgG (100% reactivity), with reduced reactivity for mouse IgG (30%).
APPLICATION HIGHLIGHTS — HIGH-VALUE RESEARCH NICHES
- One reagent, many species: high, equivalent reactivity with human, rabbit and goat IgG removes the need to stock several species-specific HRP conjugates and eliminates a common source of inter-assay variability.
- Low cross-reactivity with IgA, IgM and albumin: <5% for human IgA and IgM and <0.2% for serum albumin, so it can be used directly on serum and plasma samples with low background.
- Fc-directed binding: Protein G binds the Fc region and leaves the antigen-binding site free, giving clean detection of intact IgG and of IgG-antigen complexes.
- Hybridoma and clone screening: a single conjugate detects rabbit and goat polyclonal bleeds and reads out immunisation titres across a mixed antibody panel.
- Broader IgG-subclass coverage than Protein A: Protein G binds IgG subclasses that Protein A engages weakly, which matters when working with human IgG3 or with rat and goat IgG.
