title: Molecular cloning of the Atlantic cod chymotrypsinogen B.
abstract: The cDNA encoding Atlantic cod (Gadus morhua) chymotrypsinogen B has been isolated and sequenced. Its deduced amino acid sequence consists of a 16-residue signal sequence and a mature polypeptide of 247 residues, being two residues longer than its vertebrate analogs. This mature polypeptide corresponds to a calculated molecular mass of 26.5 kDa and shares 70% sequence identity with cod chymotrypsinogen A. However, the identity between cod chymotrypsinogen B and its other vertebrate analogues is 63-66%. In common with most fish serine proteases, cod chymotrypsinogen B contains a high number of methionine residues. The presence of a threonine instead of a highly conserved serine residue at position 189 is a novel characteristic of this enzyme. Cod chymotrypsin B, as its type B vertebrate analogs, has an alanine at position 226, whereas a glycine is most commonly found at this position in the type A chymotrypsins.
authors.affiliation: Department of Food Science, Science Institute, University of Iceland, Reykjavík.
authors.forename: R
authors.initials: R
authors.lastname: Spilliaert
authors.forename: A
authors.initials: A
authors.lastname: Gudmundsdóttir
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002919:Chymotrypsinogen / Q000235:genetics*; D003001:Cloning, Molecular; D005399:Fishes / Q000235:genetics*; D015723:Gene Library; D008969:Molecular Sequence Data; D010802:Phylogeny; D021382:Protein Sorting Signals / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: D021382:Protein Sorting Signals; D002919:Chymotrypsinogen