Open AccessUnusual cardioactive peptide (CCAP) from pericardial organs of the shore crab Carcinus maenas
Author(s) -
Joachim Stangier,
Caroline Hilbich,
Konrad Beyreuther,
Rainer Keller
Publication year - 1987
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.84.2.575
Subject(s) - carcinus maenas , peptide , neuropeptide , biology , carboxypeptidase a , biochemistry , chronotropic , hemolymph , vasopressin , decapoda , crustacean , carboxypeptidase , endocrinology , zoology , heart rate , receptor , blood pressure , enzyme
An unusual crustacean cardioactive peptide (CCAP) from the pericardial organs of the shore crabCarcinus maenas has been purified to homogeneity by a two-step reversed-phase HPLC procedure. Manual microsequencing using the 4-(N,N -dimethylamino)azobenzene 4′-isothiocyanate/phenylisothiocyanate double-coupling technique and automated gas-phase sequencing of the oxidized peptide revealed that CCAP is a nonapeptide (M r 957) of the sequence Pro-Phe-[unk]Cys-Asn-Ala-Phe-Thr-Gly-Cys-NH2 . We have confirmed the sequence by chemical synthesis of the C-terminally amidated and nonamidated forms of the peptide. The presence of the amide group was indicated by lack of susceptibility to carboxypeptidase A and Y treatment and was confirmed by the observation that the native CCAP comigrated with the amidated synthetic peptide on HPLC. Native and synthetic CCAP displayed high accelerating activity on a semi-isolated crab heart preparation, whereas the nonamidated synthetic peptide was of much lower potency. The effect of CCAP was both inoand chronotropic. The two pericardial organs of one animal yielded 30-40 pmol of extractable CCAP. Its sequence does not resemble that of any known neuropeptide. However, a “mirror-image” similarity to vasopressin is conspicuous.