Rat PENK/Proenkephalin ELISA Kit

From Assay Genie, this Sandwich ELISA kit uses a double-antibody format with colorimetric detection to measure proenkephalin (PENK) in rat-derived samples. The assay is validated for serum, plasma, cell culture supernatant, cell or tissue lysate, and other liquid samples. Proenkephalin is a precursor protein for endorphins and enkephalin peptides involved in pain perception, stress response, and addiction, supporting studies of pain management, substance abuse, and stress-related disorders in preclinical rat models.

Reagents are stored at 2–8 °C for up to 12 months. Linearity across 1:2, 1:4, and 1:8 dilutions gave 90–103% to 87–99% for serum, 85–102% to 81–95% for EDTA plasma, and 86–102% to 86–96% for heparin plasma. Recovery averaged 95% in serum, 97% in EDTA plasma, and 91% in heparin plasma. Provided components include a pre-coated microplate, lyophilized standard, biotin-labeled detection antibody, HRP-streptavidin conjugate (SABC), TMB substrate, sample and antibody dilution buffers, wash buffer, stop solution, plate sealer, and a technical manual.

The protocol involves equilibrating reagents to room temperature and loading standards, samples, and blanks onto the pre-coated plate for a 90-minute antigen-binding incubation at 37 °C. After addition of the biotin-labeled detection antibody (60 minutes at 37 °C) and HRP-streptavidin (30 minutes at 37 °C), TMB substrate is added for 10–20 minutes in the dark, followed by stop solution and absorbance measurement at 450 nm. Sample preparation differs by matrix: serum is clotted then centrifuged; plasma is collected with anticoagulant and centrifuged at 1000 × g; tissue is homogenized in PBS with protease inhibitors; cell culture supernatant is clarified; and cell lysates are prepared with lysis buffer containing protease inhibitors.