Characterization of a novel streptokinase produced by Streptococcus equisimilis of non-human origin.

This study investigates a novel form of the protein streptokinase, produced by Streptococcus equisimilis from horses, discovering it possesses unique properties and greater diversity than the previously understood forms of this protein.

Introduction

• The research revolves around streptokinases, which are proteins produced by certain forms of hemolytic streptococci, a type of bacteria. These proteins have the capacity to activate plasminogen, a precursor to the enzyme plasmin, involved in the breaking down of blood clots.

Methodology

• The researchers studied isolates from horse streptococci which produced streptokinases, named in this context Equine Streptokinases (ESKs). These ESKs showed the ability to bind both human and equine (horse) plasminogen but predominantly activated equine plasminogen.
• This distinction was used to purify a representative ESK through a process known as affinity chromatography with human plasminogen.
• The purification led to an isolated molecule, designated ‘M(r) approximately 49,000’, with two isoforms, that denotes the molecular weight of the molecule.

Comparison with Other Streptokinases

• This isolated ESK was then compared to other well-studied streptokinases, identified as Human Streptokinases (HSKs), which are known to efficiently activate human plasminogen.
• Differences between the ESK and the HSKs were identified in several areas including the highly conserved amino-terminal amino acid sequence, antigenic properties, and peptide maps, which are all used in identifying and classifying proteins.
• These differences were supported further by DNA hybridization studies which is a molecular biology method to study the presence and measuring the amount of specific DNA or RNA molecules in cells or tissues.

Conclusion

• The findings from the research indicate a much greater diversity in the family of proteins termed as streptokinases than previously understood or reported. This suggests more room for future study and potential application in the medical and biological fields.