DETERMINATION OF THE AMINO-ACID-SEQUENCE OF THE MOLT-INHIBITING HORMONE FROM THE EDIBLE CRAB, CANCER-PAGURUS

Putative moult-inhibiting hormone (MIH) from sinus glands of the edibl e crab Cancer pagurus was characterized by high-performance liquid chr omatography, followed by fractional bioassay (inhibition of ecdysteroi d synthesis by Y-organs) and immunoassay (using antisera raised agains t Carcinus MIH). This peptide was fully sequenced by automated Edman d egradation of endoproteinase-derived fragments. C. pagurus MIH is a 78 residue peptide (M(r) 9194), with free N- and C-termini and three int rachain disulphide bridges. Comparison with previously published MIH s equences confirms a high degree of sequence identity (c. 80%), support ing the view that brachyurans (crabs), possess distinct, structurally similar MIH neuropeptides.