Beta-endorphin is an endogenous opioid neuropeptide found in neurons of both the central and peripheral nervous system. It is one of five endorphins found in humans, i.e. alpha-endorphin, gamma-endorphin, alpha-neoendorphin, and beta-neoendorphin. Beta-endorphin is a 31-aa peptide resulting from processing of the precursor proopiomelanocortin (POMC). Beta-endorphin is an agonist of the opioid receptors (mu-opioid receptor in brain and mu- and kappa-receptors in spinal cord). It is used as an analgesic to numb pain.Human: H-Tyr-Gly-Gly-Phe-Met-Thr-Ser-Glu-Lys-Ser-Gln-Thr-Pro-Leu-Val-Thr-Leu-Phe-Lys-Asn-Ala-Ile-Ile-Lys-Asn-Ala-Tyr-Lys-Lys-Gly-Glu-OH or H-YGGFMTSEKSQTPLVTLFKNAIIKNAYKKGE-OH