AGRP, human, recombinant
Recombinant Human Agouti–Related Protein
Agouti-related protein is an endogenous antagonist of hypothalamic alpha-melanocortin receptors MC3R and MC4R with potent orexigenic activity. Although a complete deletion of the AGRP gene does not produce any significant metabolic phenotypes, reduction in AGRP expression by RNA interference is associated with increased metabolic rate along with reduced weight gain. In hypothalamus, it is produced by neurons in the medial portion of arcuate nucleus, which produce also the potent orexigenic peptide Neuropeptide Y (NP-Y). Another site of central AGRP production is the hypothalamic nucleus. AGRP encompasses 132 amino acid residues and its alpha-melanocortin inhibiting activity results in a 34 amino acid cystine knot domain within the C-terminal (87-132) portion of the protein. Both AGRP and NP-Y expression was shown to be suppressed by leptin. Central administration of AGRP induces hyperphagia and increased gain in body weight in rodents, but may also exert metabolic effects even when hyperphagia is prevented. In the absence of hyperphagia, intracerebralventricular administration of AGRP caused significant increases in plasma leptin and insulin concentrations (twofold and 1.5-fold, respectively) and fat pad mass. In the periphery, AGRP mRNA was found in adrenal glands, lung, testis, ovary, skeletal muscle and adipose tissue in humans or rodents. In the adrenals, it was shown that AGRP antagonizes glucosteroid production mediated by MC4R. AGRP could then modulate locally the functions of some peripheral tissues such as adrenals. In human and rat serum, detectable levels of AGRP-like activity were reported in the lower picogram range. The serum AGRP levels were elevated in obese humans compared to lean controls and increased with fasting in rats.
The human AGRP has been produced as a His-tagged (N-terminal) fusion protein in E. coli. It has a MW is 14.4 kDa (calculated) protein containing 112 amino acid residues of the human AGRP and 16 additional amino acid residues – His Tag, thrombin cleavage site. It has been purified by proprietary chromatographic techniques.
|Molecular Mass||see Desciption|
|Formulation||White (freeze-dried) powder. Lyophilized from a sterile-filtered protein solution (0.50 mg/ml) in 5 mM Tris, 25mM NaCl (pH 7.50).|
|Reconstitution||Please Note: Always centrifuge product briefly before opening vial. For reconstitution, add deionized water to prepare a working stock solution of approximately 0.50 mg/ml and let the lyophilized pellet dissolve completely. This solution can then be diluted into other aqueous buffers and stored at -20°C for future use.|
|Purity||Greater than 95% (determined by SDS-PAGE analysis).|
|Endotoxin Level||< 0.10 ng per µg protein (1EU/µg).|
|Stability & Storage||The lyophilized protein, though stable at room temperature for up to 3 weeks, is best stored desiccated at -20°C. Reconstituted protein should be used immediately or stored long-term in undiluted working aliquots at -20°C. Avoid repeated freeze-thaw cycles.|