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Isolation and characterization of cDNAs from Atlantic cod encoding two different forms of trypsinogen
A Gudmundsdóttir1, E Gudmundsdóttir, S Oskarsson
1Science Institute, University of Iceland, Reykjavík.
European Journal of Biochemistry
|November 1, 1993
Summary
Atlantic cod trypsinogen cDNAs were sequenced, revealing two anionic forms. These cod trypsins share structural features with mammalian trypsins but have unique signal peptides and activation sequences.
Area of Science:
- Biochemistry
- Molecular Biology
- Genomics
Background:
- Atlantic cod trypsinogen exists in multiple anionic forms.
- Understanding trypsinogen structure-function relationships is crucial in enzymology.
Purpose of the Study:
- To isolate and sequence the cDNAs encoding two anionic forms of Atlantic cod trypsinogen.
- To compare the structural features of Atlantic cod trypsin with mammalian trypsins.
Main Methods:
- cDNA isolation and sequencing.
- Amino acid sequence analysis.
- Comparative structural analysis.
Main Results:
- Sequenced two distinct anionic Atlantic cod trypsinogen cDNAs, yielding preproenzymes of 241 amino acids.
- Cod trypsins (222 residues) possess conserved catalytic triads (His57, Asp102, Ser195), Asp189, and six disulfide bonds.
- Isozymes differ by eight amino acids and four charges; cod trypsins are shorter than mammalian counterparts due to a proline deletion at position 152 and exhibit high methionine content.
- Cod preproenzyme signal and activation peptides show significant divergence from mammalian analogues.
- Atlantic cod and bovine trypsins share approximately 60% amino acid identity.
Conclusions:
- The study elucidates the molecular basis of Atlantic cod trypsin isozymes.
- Cod trypsins exhibit conserved functional domains but distinct signal/activation peptides compared to mammals.
- Structural variations may influence substrate specificity or regulatory mechanisms in Atlantic cod trypsin.