Human RBP4 Quantikine ELISA Kit Summary

Product Summary

The Quantikine Human RBP4 immunoassay is a 2.5 hour solid phase ELISA designed to measure human RBP4 in cell culture supernates, serum, plasma, urine, and saliva. It contains NS0-expressed recombinant human RBP4 and has been shown to accurately quantitate the recombinant factor. Results obtained using natural human RBP4 showed linear curves that were parallel to the standard curves obtained using the Quantikine kit standards. These results indicate that this kit can be used to determine relative mass values for naturally occurring human RBP4.

Preparation and Storage

Background: RBP4/Retinol-Binding Protein 4

Retinol-binding protein 4 (RBP4) is a Lipocalin superfamily molecule that transports vitamin A (retinol) and retinaldehyde in the serum. Retinaldehyde is the critical chromophore in the rhodopsin photoreceptor, while both it and retinoic acid regulate a multitude of cellular differentiation and proliferation effects through the intracellular receptors RAR and RXR. RBP4 is secreted primarily by hepatocytes and adipocytes into the blood where the RBP4-retinol complex interacts with transthyretin (TTR). Formation of the complex with TTR increases the serum half-life of RBP4 by preventing RBP4 filtration through the kidney. The C-terminally processed forms of RBP4, which do not bind TTR, are normally excreted into the urine but accumulate in the serum during renal failure. RBP4 promotes hyperglycemia, and its upregulation in visceral and liver adipocytes leads to elevated serum levels.

Assay Procedure

Refer to the product datasheet for the complete assay procedure.

Bring all reagents and samples to room temperature before use. It is recommended that all samples, standards, and controls be assayed in duplicate.

1、Prepare all reagents, standard dilutions, and samples as directed in the product insert.

2、Remove excess microplate strips from the plate frame, return them to the foil pouch containing the desiccant pack, and reseal.

3、Add 50 μL of Assay Diluent to each well.

4、Add 50 μL of Standard, control, or sample to each well. Cover with a plate sealer, and incubate at room temperature for 2 hours.

5、Aspirate each well and wash, repeating the process 4 times for a total of 5 washes.

6、Add 100 μL of Conjugate to each well. Cover with a new plate sealer, and incubate at room temperature for 2 hours.

7、Aspirate and wash 5 times.

8、Add 100 μL Substrate Solution to each well.

9、Add 100 μL of Stop Solution to each well. Read at 450 nm within 30 minutes. Set wavelength correction to 540 nm or 570 nm.