Neuropeptide-amidating activity in the radial nerve cord of Asterias rubens

摘要

Many metazoan neuropeptides are amidated at their C-terminal end and this amidation appears to be critical for the biological activity of the neuropeptide. The only enzyme known to catalyse this important posttranslational modification is peptidylglycine a-amidating monooxygenase (PAM). PAM is a bifunctional enzyme made of two subunits: the peptidylglycine α-hydroxylating monooxygenase (PHM), requiring copper for its action, and the peptidyl-α-hydroxyglycine α-amidating lyase (PAL). In this study, we investigated the presence PAM-like enzymatic activity in an echinoderm. Extracts from radial nerve cords of the sea starAsterias rubens were incubated in vitro with fluorescent peptide substrata in the presence or absence of Cu~(++). The results demonstrate a Cu~(++)-dependent amidation activity similar to the PAM action in other metazoans.