Biomedical subjects
Publications and source records attributed to S Oskarsson.
A cDNA clone encoding a psychrophilic cod chymotrypsinogen has been isolated and characterized. The predicted amino acid sequence reveals a preproenzyme of 263 amino acids containing a unique 18 residue signal sequence. Amino acid sequence identity between the cod and mammalian chymotrypsinogens is 64-68%. Two highly conserved proline residues are substituted in cod chymotrypsin.
The cDNAs encoding two different anionic forms of Atlantic cod trypsinogen have been isolated and sequenced. The nucleotide sequences include the 5'-noncoding and 3'-noncoding regions in addition to preproenzymes of 241 amino acids. These consist of hydrophobic signal peptides, activation hexapeptides and trypsins of 222 amino acid residues. The cod trypsins contain all the major structural features common to trypsins such as the catalytic triad His57, Asp102 and Ser195. Furthermore, the obligatory Asp189 and the six disulphide bonds are conserved. Eight amino acid residues are different between the isozymes, leading to a difference of four charges. Both cod trypsins are one-amino-acid-residue shorter than most mammalian trypsins as a result of deletion of proline at position 152, and have a high methionine content. In addition, the cod preproenzyme signal and activation peptides differ markedly from their mammalian analogues. The amino acid identity between the cod and bovine trypsins is approximately 60%.