
The first 16 amino acids are identical to α-endorphin.

The amino acid sequence is: 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 (31 amino acids).

It is one of three endorphins that are produced in humans, the others of which include α-endorphin and γ-endorphin.
