| RBP-4

Retinol binding protein 4, also known as RBP4, is a transporter protein for retinol (vitamin A alcohol). RBP4 has a molecular weight of approximately 21 kDa and is encoded by the RBP4 gene. RBP4 is a single polypeptide chain with a hydrophobic pocket where retinol binds. The RBP4-retinol complex then binds transthyretin in circulation to prevent renal filtration of RBP4. It is mainly, though not exclusively, synthesized in the liver and circulates in the bloodstream as a hepatokine bound to retinol in a complex with transthyretin. RBP4 has been a drug target for ophthalmology research due to its role in vision.
 

| Typical data

As the OD values of the standard curve may vary according to the conditions of the actual assay performance (e.g. operator, pipetting technique, wash technique or temperature effects), the operator should establish a standard curve for each test. Typical standard curve and data are provided below for reference only.

 

Concentration (ng/mL)	20	10	5	2.5	1.25	0.62	0.31	0
OD	2.12	1.58	1.14	0.77	0.53	0.35	0.24	0.08
Corrected OD	2.04	1.5	1.06	0.69	0.45	0.27	0.16	-

 

| Repeatability

Intra-assay Precision (Precision within an assay)：CV% < 10%; Inter-assay Precision (Precision between assays)：CV% < 10%
 

| Recovery

The recovery of Rat RBP-4 spiked at three different levels in samples throughout the range of the assay was evaluated in various matrices.

 

Sample Type	Range(%)	Average Recovery(%)
Serum(n=8)	85-101	96
Plasma(n=8)	92-105	102

 

| Linearity

Samples were spiked with high concentrations of Rat RBP-4 and diluted with Universal Diluent to produce samples with values within the range of the assay.

 

		Serum(n=4)	Plasma(n=4)
1 : 2	Range (%)	84-95	88-96
	Average (%)	91	93
1 : 4	Range (%)	89-103	87-108
	Average (%)	94	98