Isolation and partial characterization of elastase from dog granulocytes

Area of Science:

• Biochemistry
• Enzymology
• Proteomics

Background:

• Granulocytes are key immune cells containing enzymes like elastase.
• Understanding the properties of animal elastases aids comparative studies with human counterparts.
• Elastolytic enzymes play roles in physiological and pathological processes.

Purpose of the Study:

• To isolate and characterize elastolytic enzyme from dog granulocyte leukocytes.
• To compare the properties of dog granulocyte elastase with human granulocyte elastase.
• To generate an antiserum for further immunological studies.

Main Methods:

• Purification involved granula fraction preparation, Sephadex G-75 chromatography, and SP-Sephadex C-50 ion-exchange chromatography.
• Enzyme homogeneity and molecular weight were assessed using analytical and SDS-PAGE electrophoresis.
• Enzyme activity, kinetics (Km), and pH optimum were determined. Active-site titration confirmed enzyme purity.

Main Results:

• An elastolytic enzyme was purified to homogeneity from dog granulocytes.
• The enzyme has a molecular weight of 24,800 Da, lacks tyrosine and lysine, with phenylalanine as the N-terminal amino acid.
• Dog granulocyte elastase demonstrated similar substrate specificity and activity profiles to human granulocyte elastase, with a Km of 2.50 mM and pH optimum of 8.5.

Conclusions:

• Dog granulocyte elastase is a cationic protein with characteristics comparable to human granulocyte elastase.
• The purified enzyme is highly active and suitable for further functional and immunological investigations.
• A monospecific antiserum was successfully produced against the purified dog granulocyte elastase.