Human GPR81 ELISA Kit (HUFI04049)

Beyond the kit's primary metabolic and oncology applications, the Assay Genie Human GPR81 immunoassay targets the seven-transmembrane receptor encoded on chromosome 12q24.31 (UniProt Q9BXC0), a 347-residue protein first cloned by PCR from a human genomic library. The capture antibody is specific to the human HCAR1 sequence and shows no significant cross-reactivity with homologous lactate-binding receptors GPR109A and GPR109B, which are clustered at the same 12q24.31 locus. Serum is prepared by allowing whole blood to clot, centrifuging at 1000 x g for 20 min, and aliquoting the supernatant, while plasma is collected in EDTA or heparin tubes and centrifuged at 1000 x g for 15 min before storage at -20 °C or -80 °C; cell lysates and tissue homogenates are clarified at 5000 x g for 5 min. The workflow uses primary incubation at 37 °C for 90 min, biotinylated detection antibody binding at 37 °C for 60 min, and HRP-streptavidin at 37 °C for 30 min, with TMB color development protected from light for 10 to 20 min before adding the stop solution. Spiked recovery in human serum typically falls within 85 to 105%, supporting quantitative comparison of GPR81 levels across treatment cohorts. The kit is supplied for research use only and is intended to be paired with downstream western blot or qPCR confirmation of transcriptional versus protein-level receptor changes.