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Purification and partial characterization of camel anionic chymotrypsin
1Department of Biological Sciences, University of Essex, Colchester, United Kingdom.
Archives of Biochemistry and Biophysics
|January 22, 1998
Summary
Researchers isolated and characterized an anionic chymotrypsin-like enzyme from camel pancreas. This camel enzyme exhibits distinct substrate specificity and hydrolytic activity compared to bovine chymotrypsin.
Area of Science:
- Biochemistry
- Enzymology
- Comparative Proteomics
Background:
- Chymotrypsin-like enzymes are crucial serine proteases involved in various physiological processes.
- Understanding the structural and functional diversity of chymotrypsins across species provides insights into enzyme evolution and function.
- Camel pancreatic enzymes represent a largely unexplored area for biochemical characterization.
Purpose of the Study:
- To isolate and purify an anionic chymotrypsin-like enzyme from camel pancreas.
- To characterize the biochemical properties, including molecular mass, isoelectric point, pH optimum, and substrate specificity.
- To compare the camel enzyme's characteristics with those of known chymotrypsins, particularly bovine chymotrypsin.
Main Methods:
- Enzyme isolation using a three-step purification process: anion-exchange chromatography, gel filtration, and hydrophobic interaction chromatography.
- Homogeneity assessment via native and SDS gel electrophoresis and gel isoelectric focusing.
- Determination of molecular mass, isoelectric point, pH optimum, and substrate specificity using various ester substrates and enzyme kinetics assays.
Main Results:
- A homogeneous anionic chymotrypsin-like enzyme was successfully purified from camel pancreas.
- The enzyme has a molecular mass of 28.5 kDa and an isoelectric point of 4.4.
- It exhibits significantly different substrate specificity compared to bovine chymotrypsin A, with lower activity on tyrosine, tryptophan, and phenylalanine esters but higher activity on leucine ester.
- The camel enzyme has a pH optimum of 7.8, lower kininase activity, and increased susceptibility to inhibitors compared to bovine cationic chymotrypsin.
Conclusions:
- The purified camel enzyme is an anionic chymotrypsin, sharing similarities in size, charge, and substrate specificity with anionic chymotrypsins from other species.
- Its distinct substrate profile suggests specialized roles or adaptations in camel physiology.
- This study contributes to the understanding of camel digestive enzymes and the diversity of chymotrypsin-like proteases.