AMINO-ACID-SEQUENCES AND ACTIVITIES OF MULTIPLE HYPERGLYCEMIC HORMONES FROM THE KURUMA PRAWN, PENAEUS-JAPONICUS

By means of a single-step reversed-phase HPLC, six CHH family peptides were isolated from sinus gland extracts of the kuruma prawn, Penaeus japonicus. Five of these peptides (Pej-SGP-I, -II, -III, -V, and -VI) expressed hyperglycemic activity and were considered to be the hypergl ycemic hormones of this prawn. The amino acid sequences of the five pe ptides were determined (the amino acid sequence of Pej-SGP-III had bee n previously determined), revealing that all consisted of 72 amino aci d residues with a free amino-terminus and an amidated carboxyl-terminu s. They showed considerable sequence similarity to one another, but mu ch less similarity to Pej-SGP-IV with molt-inhibiting activity, the se quence of which had also been determined previously. Examination of th e dose-response relationship of these peptides showed that they were e qually potent but had different efficacies, which were in the order of Pej-SGP-V, -VI > -III, -I > -II corresponding well with their sequenc e characteristics. (C) 1997 Elsevier Science Inc.