Endomorphin-1 (EM-1) (

amino acid sequence Protein primary structure is the linear sequence of amino acids in a peptide or protein. By convention, the primary structure of a protein is reported starting from the amino-terminal (N) end to the carboxyl-terminal (C) end. Protein biosynthes ...

Tyr-Pro-Trp-Phe-NH₂) is an

endogenous Endogenous substances and processes are those that originate from within a living system such as an organism, tissue, or cell. In contrast, exogenous substances and processes are those that originate from outside of an organism. For example, es ...

opioid peptide Opioid peptides are peptides that bind to opioid receptors in the brain; opiates and opioids mimic the effect of these peptides. Such peptides may be produced by the body itself, for example endorphins. The effects of these peptides vary, but th ...

and one of the two

endomorphin Endomorphins are considered to be natural opioid neurotransmitters central to pain relief. The two known endomorphins, endomorphin-1 and endomorphin-2, are tetrapeptides, consisting of Tyr-Pro-Trp-Phe and Tyr-Pro-Phe-Phe amino acid sequences resp ...

s. It is a high

affinity Affinity may refer to: Commerce, finance and law * Affinity (law), kinship by marriage * Affinity analysis, a market research and business management technique * Affinity Credit Union, a Saskatchewan-based credit union * Affinity Equity Partn ...

, highly selective

agonist An agonist is a chemical that activates a receptor to produce a biological response. Receptors are cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an antagonist blocks the action of the ago ...

of the

μ-opioid receptor The μ-opioid receptors (MOR) are a class of opioid receptors with a high affinity for enkephalins and beta-endorphin, but a low affinity for dynorphins. They are also referred to as μ(''mu'')-opioid peptide (MOP) receptors. The prototypical � ...

, and along with endomorphin-2 (EM-2), has been proposed to be the actual endogenous

ligand In coordination chemistry, a ligand is an ion or molecule (functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electr ...

of the μ-receptor. EM-1 produces

analgesia Pain management is an aspect of medicine and health care involving relief of pain (pain relief, analgesia, pain control) in various dimensions, from acute and simple to chronic and challenging. Most physicians and other health professionals ...

in animals and is

equipotent In mathematics, two sets or classes ''A'' and ''B'' are equinumerous if there exists a one-to-one correspondence (or bijection) between them, that is, if there exists a function from ''A'' to ''B'' such that for every element ''y'' of ''B'', the ...

with

morphine Morphine is a strong opiate that is found naturally in opium, a dark brown resin in poppies (''Papaver somniferum''). It is mainly used as a analgesic, pain medication, and is also commonly used recreational drug, recreationally, or to make ...

in this regard. The

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

encoding for EM-1 has not yet been identified, and it has been suggested that endomorphins could be synthesized by an enzymatic, non-ribosomal mechanism. By combining N-terminal guadino modifications, a new class of endonmorphin-1 was synthesized, the range of their bioactivities were measured by radioligand binding assay in order to conclude its potency as an opioid. Endomorphin-1 has high affinity and specificity for opioid receptors for behavioral, physiological and pharmacological assays, it is also a potent analgesic agent which brings effects on cardiovascular, respiratory and gastrointestinal functions as well as in immune system responses. This endogenous opioid peptide can help with neuropathic pain without having the common side effects many neuropathic drugs caused which produces constipation. To make this drug side effect-free, a modification at the

N-terminus The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the ami ...

by 2-aminodecainoic acid is made which in term showed an improve in the drug's metabolic stability along with improving its membrane permeability, while holding its high receptor binding affinity, helping the drug act as a potent agonist

References

Mu-opioid receptor agonists Neuropeptides {{biochemistry-stub

See also

References