Enkephalins and Proenkephalins

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CAT# Product Name M.W Molecular Formula Inquiry
E06001 [Met5,Arg6,7,Val8,Gly9] Enkephalin 1042.2 C46H71N15O11S1 Inquiry
E06002 QF-ERP7, FRET 1132.4 Inquiry
E06003 Preproenkephalin B (186-204), human 1955.0 C78H115N21O36S1 Inquiry
E06004 [Des-Tyr1] Leu-Enkephalin 392.6 C19H28N4O5 Inquiry
E06006 Leu-Enkephalin, amide 554.7 C28H38N6O6 Inquiry
E06009 [Met5]-Enkephalin 573.8 Inquiry
E06011 [Lys6] Leu-Enkephalin 683.9 C34H49N7O8 Inquiry
E06013 [Met5,Arg6] Enkephalin 729.9 C33H47N9O8S1 Inquiry
E06014 [Met5,Arg6,Phe7] Enkephalin, amide 876.1 C42H57N11O8S1 Inquiry
E06015 [Met5,Arg6,Phe7] Enkephalin 877.0 C42H56N10O9S1 Inquiry
E06016 Spinorphin, bovine 877.1 C45H64N8O10 Inquiry
E06017 [Met5,Arg6] Enkephalin-Arg 886.1 C39H59N13O9S1 Inquiry
E06018 [Met5,Arg6,Gly7,Leu8] Enkephalin 900.1 C41H61N11O10S1 Inquiry
E06019 Dermenkephalin 955.3 C44H62N10O10S2 Inquiry
E06020 Adrenorphin, Free Acid 985.2 C44H68N14O10S1 Inquiry
E06021 (Des-Tyr1)-Leu-Enkephalin 392.46 Inquiry
E06022 Carboxymethyl-Phe-Leu-OH 336.39 Inquiry
E06023 (Ala2)-Leu-Enkephalin 569.66 C29H39N5O7 Inquiry


Enkephalin (ENK) was first discovered by Hughes in 1975. It belongs to endogenous opioids and is widely distributed in the body. It binds to different types of opioid receptors and exerts various biological regulation effects. Studies have shown that enkephalin comprises two pentapeptides, Methionine enkephalin (MEK) and Leucine enkephalin (LEK), which are derived from the same precursor, proenkephalin. Effective activation of endogenous ENK allows its physiological function to be fully utilized to induce effective analgesia and enhance immune function.

Mechanism of action

ENK binds to endogenous opioid peptide receptors, and endogenous opioid peptide receptors are classified into μ, δ, κ, etc. while ENK mainly acts on δ-type receptors. The receptors are mainly located in the central nervous system and regulate the pain-related anatomical sites, which are also the areas with the highest concentration of immunoreactive ENK. ENK regulates the secretion of prolactin, thyrotropin, and growth hormone. From the structure of the ENK distribution in the edge system, it is suggested that ENK is related to emotional response. In particular, LEK has strong binding to δ receptors, and δ receptors may be involved in emotional regulation activities such as euphoria and reward behavior. Under certain conditions, MENK binds to the κ and δ receptors on the surface of immune cells and participates in cAMP-PKA, Ca2+-calmodulin, PKC and other signaling pathways, producing immunomodulatory effects.

Application of Enkephalins and Proenkephalins

The biological function of ENK plays an important role in the treatment of immune system related diseases and tumor diseases. ENK is involved in the regulation of immune and neuroendocrine systems, has immunomodulatory effects, and is also an important class of cytokines. For diabetic patients with immunodeficiency defects, ENK is expected to serve as a therapeutic to help restore the disordered immune system. ENK has anti-tumor, anti-autoimmune diseases, anti-inflammatory, anti-microbial infections and so on. The functions of ENK analgesic activity, participation in immune regulation, and changes in emotional responses are increasingly attracting attention.


  1. Chan, D. C. S., Cao, T. H., & Ng, L. L. (2017). Proenkephalin in Heart Failure. Heart failure clinics.
  2. Burtscher, J., & Schwarzer, C. (2017). The Opioid System in Temporal Lobe Epilepsy: Functional Role and Therapeutic Potential. Frontiers in molecular neuroscience, 10, 245.
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