A thrombin-like enzyme from timber rattlesnake venom

Area of Science:

• Biochemistry
• Toxicology
• Molecular Biology

Background:

• Snake venom contains various enzymes with diverse biological activities.
• Procoagulant enzymes from venom play a significant role in hemostasis and thrombosis research.

Purpose of the Study:

• To isolate and characterize the procoagulant component from timber rattlesnake (Crotalus horridus horridus) venom.
• To elucidate the mechanism by which this venom component induces blood clotting.

Main Methods:

• Purification using sequential chromatography: DEAE-cellulose ion-exchange, affinity chromatography on p-aminobenzamidine, and DEAE-Sepharose.
• Characterization by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and discontinuous gel electrophoresis.
• Amino acid analysis and enzymatic activity assays.

Main Results:

• A single procoagulant protein of Mr 29,500 +/- 2000 was purified, showing some carbohydrate presence.
• The purified component specifically catalyzed the hydrolysis of the A fibrinopeptide from fibrinogen's A alpha-chain.
• The enzyme was inhibited by phenylmethylsulfonyl fluoride, indicating an active-center serine, but not by trypsin inhibitors.

Conclusions:

• The purified timber rattlesnake venom component is a serine protease that specifically activates fibrinogen.
• This finding contributes to understanding snake venom toxins and their interactions with the coagulation cascade.
• The characterized procoagulant may serve as a valuable tool in hemostasis research.