one of them , namely met-enkephalin ( h-tyr-gly-gyl-phe-met-oh ) is likely to be a fragment of the peptides alpha- and beta-endorphin , both showing opioid-like actions , as well as of beta-lipotropin , a polypeptide showing no opioid-like activity : all these peptides include the pentapeptide met-enkephalin within their molecules . beta-liportropin and acth are likely to be fragments of a common precursor .
C0030935
fragment
C0030956
peptides