Partial characterization and amino acid composition of a high molecular weight peptide with salmon calcitonin immunoreactivity in a crustacean: Nephrops norvegicus.

Anti-salmon calcitonin antibodies were used to follow the purification of a high molecular weight peptide present both in the haemolymph and in the hepatopancreas of the Norway lobster Nephrops norvegicus. An apparent molecular weight of 22 kDa has been measured in electrophoresis on SDS gels and amino acid composition compared to salmon calcitonin. The amount determined by the immunoreactivity assay corresponds to about 1/40 and 1/140 of that which is based on direct protein measurement for the hepatopancreas and the haemolymph respectively. The total amount of this peptide could be estimated as 3.5 mg/g fresh weight for the hepatopancreas and 140 ug/ml for the haemolymph. The function of this peptide is still unknown.