Amino acid sequence of dimeric myoglobin from Cerithidea rhizophorarum.

The complete amino acid sequence of the dimeric myoglobin from Cerithidea rhizophorarum, a common gastropodic mollusc on the Japanese coast having an elongated many-whorled shell, has been determined. The monomer is composed of 151 amino acid residues, is acetylated at the amino terminus, and 75 residues out of 151 are homologous with the monomer of myoglobin from the whelk Busycon canaliculatum. Unlike Aplysia myoglobin, which lacks the distal histidine, Cerithidea myoglobin contains three histidines in its monomer, His-66 being assigned to the distal position, and in its oxymyoglobin form its stability properties show a very strong pH dependence.