Hu Leptin, 2 mg

Human recombinant Leptin from STEMCELL Technologies is a small, non-glycosylated protein expressed in E. coli and derived from the ob or lep gene. It acts as both a metabolic hormone and a proinflammatory cytokine that induces Th1 immune responses, and is a member of the gp130 family of cytokines correlated with obesity. The protein can promote osteogenesis via osteoblast receptors and inhibit bone formation through hypothalamic action. Leptin binds the leptin receptor OB-R, which exists in six isoforms in humans, and through LepRb activates JAK2, triggering downstream signaling via SHP-2, STAT5, and STAT3. Reported biological activities include the induction of cell proliferation and morphological differentiation in hematopoietic cell lines, chondrocytes, and hepatic cells. Listed alternative names include LEP, OB, Obese protein, Obesity factor, and OBOBS.

The product corresponds to accession NP_000221.1 (Val22–Cys167) with a predicted molecular mass of 16 kDa, and is supplied lyophilized from sterile PBS at pH 7.4. Trehalose (5%–8%), mannitol, and 0.01% TWEEN® 80 are normally added as protectants before lyophilization. The manufacturer reports purity of ≥ 95% and an endotoxin level of ≤ 1.0 EU/μg protein measured by kinetic Limulus amebocyte lysate (LAL) analysis. Binding activity was tested by functional ELISA, in which immobilized recombinant leptin at 2000 ng/mL bound human leptin receptor (His & hFc tag) with a linear range of 70–420 ng/mL.

Storage is at -20 °C to -80 °C; the product is stated to be stable as supplied for 12 months from the date of receipt. For preparation, the vial is centrifuged before opening and reconstituted in sterile water to at least 0.1 mg/mL without vortexing. The product is intended for research use only and not for human or animal diagnostic or therapeutic uses unless otherwise stated.