Human Ubiquitin (Ub) ELISA Kit

Principle of the Assay

The microtiter plate provided in this kit has been pre-coated with an antibody specific to Ub. Standards or samples are then added to the appropriate microtiter plate wells with a biotin-conjugated antibody preparation specific to Ub. 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 Ub, 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 Ub 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

UbiquitinExists either covalently attached to another protein, or free (unanchored). When covalently bound, it is conjugated to target proteins via an isopeptide bond either as a monomer (monoubiquitin), a polymer linked via different Lys residues of the ubiquitin (polyubiquitin chains) or a linear polymer linked via the initiator Met of the ubiquitin (linear polyubiquitin chains). Polyubiquitin chains, when attached to a target protein, have different functions depending on the Lys residue of the ubiquitin that is linked: Lys-6-linked may be involved in DNA repair; Lys-11-linked is involved in ERAD (endoplasmic reticulum-associated degradation) and in cell-cycle regulation; Lys-29-linked is involved in proteotoxic stress response and cell cycle; Lys-33-linked is involved in kinase modification; Lys-48-linked is involved in protein degradation via the proteasome; Lys-63-linked is involved in endocytosis, DNA-damage responses as well as in signaling processes leading to activation of the transcription factor NF-kappa-B. Linear polymer chains formed via attachment by the initiator Met lead to cell signaling. Ubiquitin is usually conjugated to Lys residues of target proteins, however, in rare cases, conjugation to Cys or Ser residues has been observed. When polyubiquitin is free (unanchored-polyubiquitin), it also has distinct roles, such as in activation of protein kinases, and in signaling.

GENE ID	7314
SWISS PROT	P0CG47
SYNONYMS	Ubiquitin B; UbB; Ubiquitous Immunopoietic Polypeptide; Polyubiquitin B

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 Ub were tested 20 times on one plate, respectively. Inter-assay Precision (Precision between assays): 3 samples with low, middle, and high-level Ub 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 25.4pg/mL.
ASSAY RANGE	62.5-4000pg/mL
SPECIFICITY	This assay has high sensitivity and excellent specificity for the detection of Ub. No significant cross-reactivity or interference between Ub and analogs was observed. Note: Limited by current skills and knowledge, it is impossible to perform all possible cross-reactivity detection tests between Ub and all analogs, therefore, cross reactivity may still exist.