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Purification of a plasminogen activator from Streptococcus uberis
1Institute for Animal Health, Compton, Newbury, Berkshire, UK.
FEMS Microbiology Letters
|May 1, 1994
Summary
Streptococcus uberis secretes a novel protein that activates plasminogen in cattle, horses, and sheep. This protein, likely a dimer, was purified and partially characterized using monoclonal antibodies.
Area of Science:
- Microbiology
- Biochemistry
- Immunology
Background:
- Streptococcus uberis is a significant pathogen in animal mastitis.
- Plasminogen activation plays a role in tissue remodeling and bacterial virulence.
Purpose of the Study:
- To purify and characterize a plasminogen-activating protein from Streptococcus uberis.
- To investigate the species specificity of the protein's activity.
Main Methods:
- Protein purification using ammonium sulphate precipitation and molecular exclusion chromatography.
- Molecular mass determination via SDS-PAGE.
- Assessment of plasminogen activation in various species.
- Monoclonal antibody inhibition assays.
Main Results:
- A protein with plasminogen-activating properties was isolated from Streptococcus uberis.
- The protein specifically activated bovine, equine, and ovine plasminogen, but not human or porcine plasminogen.
- The native protein has an estimated molecular mass of 57 kDa, while SDS-PAGE indicated a 29 kDa subunit, suggesting a dimeric structure.
- Three of five monoclonal antibodies inhibited the protein's activity.
Conclusions:
- Streptococcus uberis produces a species-specific plasminogen activator.
- The protein's dimeric structure and inhibitory antibodies provide targets for further research.
- Understanding this protein may offer insights into Streptococcus uberis pathogenesis.