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Purification and partial characterization of feline trypsin
J M Steiner1, T L Medinger, D A Williams
1Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, IN 47907, USA. JMS@vct.purdue.edu
Summary
Researchers purified and characterized feline trypsin and trypsinogen, identifying only one isoform in domestic cats. This cationic enzyme is crucial for understanding feline digestive physiology and related research.
Area of Science:
- Biochemistry
- Zoology
Background:
- Trypsins are key digestive enzymes found across many species.
- Characterization of feline trypsin has been notably absent in scientific literature.
- Multiple trypsin isoforms are common in various mammalian and nonmammalian species.
Purpose of the Study:
- To purify and characterize trypsin and its zymogen (trypsinogen) from the domestic cat (Felis catus).
- To determine the number of trypsin isoforms present in cats.
- To analyze the physicochemical properties and N-terminal sequence of feline trypsinogen.
Main Methods:
- Purification of feline trypsin using sulfuric acid extraction, ammonium sulfate fractionation, gel filtration, and affinity chromatography.
- Purification of feline trypsinogen via sulfuric acid extraction, SDS-PAGE, and electroelution.
- Isoelectric focusing, molecular weight estimation, and N-terminal amino acid sequencing.
Main Results:
- A single isoform of feline trypsin and trypsinogen was successfully isolated and purified.
- Both feline trypsinogen and trypsin exhibited a high isoelectric point (>10.0), indicating cationic properties.
- The molecular weights were estimated at 22,600 Da for trypsinogen and 21,000 Da for trypsin.
- The N-terminal amino acid sequence of feline trypsinogen showed homology to other mammalian species.
Conclusions:
- Domestic cats appear to possess only one detectable isoform of trypsin, or others exist in minimal quantities.
- Feline trypsinogen and trypsin are confirmed to be cationic.
- The N-terminal sequence, particularly the activation peptide, shares identity with canine cationic trypsinogen, suggesting evolutionary conservation.