Leptin Protein, Human

Leptin is a cytokine-like sugar secretory protein secreted by adipocytes that helps regulate energy balance by inhibiting food intake and increasing thermogenesis. Leptin can activate the JAK2-STAT3 and PI3K-AKT/mTOR pathways to regulate energy metabolism, prolong the QT interval via MAPK in the myocardium, and play a protective role in the gastric mucosa by inducing NO/CGRP release via the vagus nerve. Circulating CRP protein binds to leptin and blocks signal transduction, leading to obesity resistance. Leptin Protein, Human is a recombinant human Leptin protein expressed by E. coli without a tag.

Leptin is a hormone secreted by adipocytes that helps regulate energy balance by inhibiting food intake and increasing thermogenesis. It belongs to the cytokine-like protein family. Leptin has a conserved four-helix bundle conformation, with a tertiary structure stabilized by disulfide bonds. It lacks a classical signal peptide but is secreted via a non-classical pathway. The C-terminal domain of leptin mediates receptor binding, while the N-terminal region promotes oligomerization. Leptin binds to the long receptor OB-Rb in hypothalamic neurons and peripheral tissues, activating the JAK2-STAT3 and PI3K-AKT/mTOR pathways, inhibiting food intake and enhancing energy expenditure. In cardiomyocytes, leptin mediates MAPK activation through OB-Rb, reducing heart rate and prolonging the QT interval, an effect that is independent of β-adrenergic signaling^[1][2][3][4].
In the gastric mucosa, leptin stimulates sensory neurons to release NO and CGRP via the vagus nerve, enhancing blood flow and protecting tissues from ischemia-reperfusion injury. Circulating C-reactive protein (CRP) binds to leptin, blocks receptor interaction and attenuates STAT3 phosphorylation, leading to leptin resistance in obesity^[3][4]. Upstream regulators of leptin include leptin secreted by adipocytes and CRP synthesized by the liver; downstream targets include STAT3, PI3K, eNOS and mTOR, which play a role in regulating metabolism, neurogenesis and vascular function^[1][4].
In metabolic diseases, leptin resistance is associated with hyperleptinemia and inhibition of CRP-mediated signaling, and leptin supplementation may inhibit congenital lipodystrophy and type 2 diabetes^[4]. At the same time, Leptin's direct effect on cardiac repolarization (QT interval prolongation) and its interaction with CRP may be involved in obesity-related arrhythmias and atherosclerosis^[2]. Leptin also enhances gastric mucosal blood flow and protects against ischemic damage through vagus-sensory nerve-mediated NO/CGRP release, and can be used in the study of peptic ulcer disease^[3].

1.The ED₅₀ as determined by a chemotaxis bioassay using human Leptin R transfected BaF3 murine proB cells is less than 2.0 ng/mL, corresponding to a specific activity of > 5.0 × 10⁵ IU/mg.
2.Immobilized Mouse LEPR (C-10His) at 10 μg/mL (100 μL/well) can bind Leptin, Human. The ED₅₀ is 17.15 ng/mL.
3.Measured in a cell proliferation assay using BaF3 mouse pro-B cells transfected with human Leptin R. The ED₅₀ for this effect is ≤1.948 ng/mL, corresponding to a specific activity is ≥5.133×10⁵ units/mg.

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  Measured in a cell proliferation assay using BaF3 mouse pro-B cells transfected with human Leptin R. The ED₅₀ for this effect is 1.948 ng/mL, corresponding to a specific activity is 5.133×10⁵ units/mg.

Human

E. coli

Tag Free

P41159 (V22-C167)

3952  [NCBI]

VPIQKVQDDTKTLIKTIVTRINDISHTQSVSSKQKVTGLDFIPGLHPILTLSKMDQTLAVYQQILTSMPSRNVIQISNDLENLRDLLHVLAFSKSCHLPWASGLETLDSLGGVLEASGYSTEVVALSRLQGSLQDMLWQLDLSPGC

Approximately 13-16 kDa

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  Greater than 95% as determined by reducing SDS-PAGE.

Lyophilized powder

Lyophilized from a 0.22 μm filtered solution of PBS, pH 7.4, 8% trehalose.

<1 EU/μg, determined by LAL method.

It is not recommended to reconstitute to a concentration less than 100 μg/mL in ddH₂O. For long term storage it is recommended to add a carrier protein (0.1% BSA, 5% HSA, 10% FBS or 5% Trehalose).

Stored at -20°C for 2 years from date of receipt. After reconstitution, it is stable at 4°C for 1 week or -20°C for longer (with carrier protein). It is recommended to freeze aliquots at -20°C or -80°C for extended storage.

Room temperature in continental US; may vary elsewhere.

• [1]. Chen K, et al. Induction of leptin resistance through direct interaction of C-reactive protein with leptin. Nat Med. 2006 Apr;12(4):425-32.  [Content Brief]

  [2]. Tsuchiya T, et al. Expression of leptin receptor in lung: leptin as a growth factor. Eur J Pharmacol. 1999 Jan 22;365(2-3):273-9.  [Content Brief]

  [3]. Lin YC, et al. Leptin decreases heart rate associated with increased ventricular repolarization via its receptor. Am J Physiol Heart Circ Physiol. 2015 Nov 15;309(10):H1731-9.  [Content Brief]

  [4]. Brzozowski T, et al. Brain-gut axis in gastroprotection by leptin and cholecystokinin against ischemia-reperfusion induced gastric lesions. J Physiol Pharmacol. 2001 Dec;52(4 Pt 1):583-602.  [Content Brief]