Apelin, an endogenous ligand for the G-protein-coupled APJ receptor, has been recently extensively studied in obesity research. It is not only expressed in adipocyte tissue, but also widely expressed in various other organs such as the heart, lung, kidney, gastrointestinal tract, brain, adrenal glands, endothelium, and human plasma.
Apelin is derived from a 77-amino-acid prepropeptide that is cleaved into a 55-amino-acid fragment and then into shorter forms. The physiologically active form is thought to be apelin 36, although the pyroglutamylated form of apelin 13, which is also produced endogenously, is more potent.
Studies have shown the association between apelin and obesity. Apelin has higher circulating levels in obesity. Insulin exerts a positive action on adipocyte apelin production. Apelin also regulates fluid homeostasis, playing an important role in the hypothalamic regulation of food and water intake, and pituitary hormone release.
In addition to its role in obesity, apelin acts as a mediator of cardiovascular control, including for blood pressure and blood flow. It is one of the most potent stimulators of cardiac contractility yet identified, and plays a role in cardiac tissue remodeling. Apelin levels are increased in left ventricles of patients with chronic heart failure and also in patients with chronic liver disease.
- Strip plates and additional reagents allow for use in multiple experiments
- Quantitative protein detection
- Establishes normal range
- The best products for confirmation of antibody array data
The capture antibody provided in this kit recognizes human, mouse and rat Apelin.
Target Protein Information
Apelin (APJ endogenous ligand) [Cleaved into: Apelin C-Terminus (APC)]
- Pre-Coated 96-well Strip Microplate
- Wash Buffer
- Standard Peptide
- Assay Diluent(s)
- Biotinylated Peptide
- TMB One-Step Substrate
- Stop Solution
- Assay Diagram
- Positive Control Sample
- Capture Antibody
- User Manual
Other Materials Required
- Distilled or deionized water
- Precision pipettes to deliver 2 µl to 1 ml volumes
- Adjustable 1-25 ml pipettes for reagent preparation
- 100 ml and 1 liter graduated cylinders
- Tubes to prepare standard and sample dilutions
- Orbital shaker
- Aluminum foil
- Saran Wrap
- Absorbent paper
- Microplate reader capable of measuring absorbance at 450nm
- SigmaPlot software (or other software that can perform four-parameter logistic regression models)
Protocol OutlinePrepare all reagents, samples and standards as instructed.Add 100 µl detection antibody to each well.Incubate 1.5 h at RT or O/N at 4°C.Add 100 µl standard or sample to each well.Incubate 2.5 h at RT.Add 100 µl prepared streptavidin solution.Incubate 45 min at RT.Add 100 µl TMB One-Step Substrate Reagent to each well.Incubate 30 min at RT.Add 50 µl Stop Solution to each well.Read plate at 450 nm immediately.
Standard, Biotinylated Apelin C-Terminus peptide, and Positive Control should be stored at -20°C after arrival. Avoid multiple freeze-thaws. The remaining kit components may be stored at 4°C. Opened Microplate Wells and antibody (Item N) may be stored for up to 1 month at 2° to 8°C. Return unused wells to the pouch containing desiccant pack and reseal along entire edge.