ISOLATION AND CHARACTERIZATION OF RED-PIGMENT-CONCENTRATING HORMONE (RPCH) FROM 6 CRUSTACEAN SPECIES

Red-pigment-concentrating hormone (RPCH) has been isolated from nerve tissue of six decapod crustaccan species. The primary structure of three of the six hormones, i.e., those of Cancer magister, Carcinus maenas and Orconectes limosus, was determined by manual microsequencing as: pELNFSPGW-NH2. This sequence is identical to that of RPCH from Pandalus borealis, the only previously known sequence of a crustacean RPCH. The other three hormones from Liocarcinus puber, Nephrops norvegicus, and Pacifastacus leniusculus could not be characterized completely. However, amino acid compositions, the presence of N-terminal pGlu, and the blocked N-terminal ends are in accordance with the primary structure established for the other three RPCHs. We suggest that all six peptides have the same amino acid sequence. These results indicate that RPCH, which is likely to be related to the peptides of the AKH family in insects, is highly conserved among crustacean species. This is in remarkable contrast to the high degree of molecular evolution exemplified by the many different AKH-like peptides among insect species. © 1990 Springer-Verlag.