Human X-Box Binding Protein 1 (XBP1) ELISA Kit

Principle of the Assay

The microtiter plate provided in this kit has been pre-coated with an antibody specific to XBP1. Standards or samples are then added to the appropriate microtiter plate wells with a biotin-conjugated antibody preparation specific to XBP1. Next, Avidin conjugated to Horseradish Peroxidase (HRP) is added to each microplate well and incubated. After the TMB substrate solution is added, only those wells that contain XBP1, biotin-conjugated antibody, and enzyme-conjugated Avidin will exhibit a change in color. The enzyme-substrate reaction is terminated by the addition of sulphuric acid solution, and the color change is measured spectrophotometrically at a wavelength of 450nm ± 10nm. The concentration of XBP1 in the samples is then determined by comparing the O.D. of the samples to the standard curve.

For Use with serum, plasma, and cell culture supernatants. For Research Use Only. Not for use in diagnostic procedures.

Target Information

Functions as a transcription factor during endoplasmic reticulum (ER) stress by regulating the unfolded protein response (UPR). Required for cardiac myogenesis and hepatogenesis during embryonic development, and the development of secretory tissues such as exocrine pancreas and salivary gland (By similarity). Involved in terminal differentiation of B lymphocytes to plasma cells and production of immunoglobulins (PubMed:11460154). Modulates the cellular response to ER stress in a PIK3R-dependent manner (PubMed:20348923). Binds to the cis-acting X box present in the promoter regions of major histocompatibility complex class II genes (PubMed:8349596). Involved in VEGF-induced endothelial cell (EC) proliferation and retinal blood vessel formation during embryonic development but also for angiogenesis in adult tissues under ischemic conditions. Functions also as a major regulator of the UPR in obesity-induced insulin resistance and type 2 diabetes for the management of obesity and diabetes prevention (By similarity).

GENE ID	7494
SWISS PROT	P17861
SYNONYMS	TREB5; XBP2; Tax-responsive element-binding protein 5

Materials Supplied

Kit Components	96 Wells Quantity/Size
Pre-coated, ready-to-use 96-well strip plate	1 plate
Plate sealer for 96 wells	2
Standard	2 tubes
Diluent buffer	1 bottle
Detection Reagent A	1 bottle
Detection Reagent B	1 bottle
TMB Substrate	1 tube
Stop Solution	1 tube
Wash Buffer (30 ℅ concentrate)	1 tube
Product data sheet	1 copy

Storage

The TMB Substrate, Wash Buffer (30X concentrate), and the Stop Solution should be stored at 4°C upon receipt, while the other items should be stored at -20°C.

Performance Characteristics

REPEATABILITY	Intra-assay Precision (Precision within an assay): 3 samples with low, middle, and high-level XBP1 were tested 20 times on one plate, respectively. Inter-assay Precision (Precision between assays): 3 samples with low, middle, and high-level XBP1 were tested on 3 different plates, with 8 replicates in each plate. CV(%) = SD/meanX100 Intra-Assay: CV<10% Inter-Assay: CV<12%
SENSITIVITY	The minimum detectable dose was 0.063ng/mL.
ASSAY RANGE	0.156-10ng/mL
SPECIFICITY	This assay has high sensitivity and excellent specificity for the detection of XBP1. No significant cross-reactivity or interference between XBP1 and analogs was observed. Note: Limited by current skills and knowledge, it is impossible to perform all possible cross-reactivity detection tests between XBP1 and all analogs, therefore, cross reactivity may still exist.