The isoelectric point of thrombin and its behaviour compared to prothrombin at some solid surfaces

Area of Science:

• Biochemistry
• Protein Chemistry
• Biophysics

Background:

• Thrombin and prothrombin are key proteins in blood coagulation.
• Understanding protein charge and surface interactions is crucial for biological processes.

Purpose of the Study:

• To determine the charge characteristics of thrombin and prothrombin at physiological pH.
• To investigate the adsorption behavior of thrombin on negatively charged surfaces.
• To assess the functional activity of adsorbed thrombin.

Main Methods:

• Isoelectric point determination for thrombin and prothrombin.
• Surface adsorption experiments using behenic acid surfaces at pH 8.2.
• Assay of fibrinogen coagulation by adsorbed thrombin.

Main Results:

• Thrombin exhibits a high isoelectric point, acting as a cation at blood pH.
• Prothrombin has a low isoelectric point, behaving as an anion at blood pH.
• Thrombin readily adsorbs to negatively charged surfaces (e.g., behenic acid) and remains active, coagulating fibrinogen.

Conclusions:

• The electric charge of thrombin influences its interaction with surfaces.
• Thrombin's cationic nature and adsorption properties are significant in the context of atherosclerosis.
• Further research into protein-surface interactions may elucidate disease mechanisms.