Human VDBP (GC Globulin) ELISA Assay Kit


Eagle Biosciences Human VDBP (GC Globulin) ELISA Assay Kit is intended for use in the quantitative determination of free and not actin complex bound Vitamin D Binding Protein (VDBP, also known as GC Globulin) in human serum and plasma.  The Human VDBP (GC Globulin) ELISA Assay Kit is for research use only and not intended for diagnostic procedures. 

SKU: DBP31-K01 Categories: , ,

Human VDBP (GC Globulin) ELISA Assay Kit

For Research Use Only

Size:  1×96 wells
Sensitivity:  0.0637 µg/mL
Dynamic Range:  0 – 20.1 µg/mL
Incubation Time:  1.5 hours
Sample Size: 10 µL
Sample Type:  Serum, Plasma

Product Developed and Manufactured in the USA

Additional Information

Assay Background

Vitamin D-binding protein (DBP) is a 58 kDa circulating glycoprotein secreted by the liver. It binds about 85% to 90% of circulating 25-OH-D2/3 and 1,25-(OH)2-D3, regulates the bioavailability of active vitamin D, and transports them to target organs. There is only less than one percent 25-OH-D2/3 is in the free form in the circulation. The full length DBP contains 476-amino acids, including a 16-amino acid signal sequence. Biologically, DBP may involve directly and indirectly in regulating bone metabolism.

Circulating DBP also binds to actin at 1:1 molecule ratio, while this protein complex is removed by kidney. In patient with trauma, sepsis or multiple organ failure, DBP concentration decreases. Urine DBP is reported to be a biomarker of major renal event in patient undergoing coronary angiography.

Assay Principle

The Eagle Biosciences Human VDBP (GC Globulin) quantitative VDBP ELISA Assay Kit is a solid phase competitive immunoassay designed to detect VDBP. Microwells are coated with anti-VDBP antibody. Assay calibrators, control and diluted unknown serum or plasma specimens are added to the microwells along with GC Globulin HRP conjugated antibody. After an incubation period, the immunocomplex of solid phase bound “VDBP Antibody-VDBP” is formed, which inhibits the formation of “VDBP Antibody – HRP Conjugated VDBP”. Unbound HRP Conjugated VDBP are removed with a washing step. During a second incubation with TMB substrate, a blue color is developed. The enzyme-substrate reaction is stopped by the addition of sulfuric acid. The absorbance of assay calibrators, controls and unknown specimens are measured by an ELISA plate reader with wavelength set at 450 nm. The color intensity is inversely proportional to the amount of VDBP present in the calibrators controls and specimens.

Assay Procedure

  1. Add 15 µl of calibrators, controls and diluted 1:200 test samples into the designated microwells.
  2. Add 100 µl HRP Conjugated VDBP to each well.
  3. Mix contents of wells gently for 5 – 10 seconds. Seal the plate securely, cover with aluminum foil, and incubate at room temperature for 60 minutes.
  4. Wash each well 5 times by dispensing 350 µL of working wash solution into each well and then completely aspirating the contents. Alternatively, an automated microplate washer can be used.
  5. Add 100 µl TMB reagent to each of the wells.
  6. Cover plate with aluminum foil, and incubate at room temperature for 20 minutes.
  7. Immediately add 100 µL of ELISA Stop Solution into each of the wells. Mix gently.
  8. Read the absorbance at 450 nm. It is recommended to use 4-parameter curve fit to calculate the sample results.

Typical Standard Curve


Product Manual