ISOLATION AND SEQUENCE ANALYSIS OF A PIGMENT-DISPERSING HORMONE FROM EYESTALKS OF THE CRAB,<i>CANCER MAGISTER</i>

Abstract

The application of separation procedures, including liquid partition, gel filtration, ion-exchange chromatography, partition chromatography, and reversed-phase high-performance liquid chromatography, enabled the purification of an octadecapeptide pigment-dispersing hormone (PDH) from powdered lyophilized eyestalks ofthe crab, Cancer magister. Automated Edman degradation, followed by the identification of carboxyl-terminal amide, established the sequence of the peptide as: Asn-Ser-Glu-Leu-Ile-Asn-Ser-Ile-Leu-Gly-Leu-Pro-Lys-Val-Met-Asn-Asp-Ala-NH2. The characterized Cancer PDH is structurally identical to an octadecapeptide PDH of Uca pugilator, but differs from the PDH of Pandalus borealis at positions 3, 4, 11, 13, 16, and 17.