title: Acidosis, magnesium and acetylsalicylic acid: effects on thrombin.
abstract: Thrombin, an enzyme from the hydrolase family, is the main component of the blood coagulation system. In ischemic stroke it acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin forming blood clots in the brain. It has been found to phosphoresce at room temperature in the millisecond and microsecond ranges. The phosphorescence of thrombin was studied under physiological conditions, in acidosis (decrease of pH from 8.0 to 5.0) and on the addition of salts (magnesium sulfate and sodium chloride) and of acetylsalicylic acid, and its connection with thrombin function is discussed. Acidosis significantly increased the internal dynamics of thrombin. We propose that lactate-acidosis plays a protective role in stroke, preventing the formation of clots. The addition of NaCl and MgSO(4) in different concentrations increased the internal dynamics of thrombin. Also, the addition of MgSO(4) decreased thrombin-induced platelet aggregation. However, magnesium sulfate and acetylsalicylic acid in the therapeutic concentrations used for treatment of ischemic stroke had no effect on thrombin internal dynamics. The data obtained will help to elucidate the conformational stability of thrombin under conditions modulating lactate-acidosis and in the presence of magnesium sulfate.
authors.affiliation: BI Stepanov Institute of Physics of NASB, Skoriny str. 68, 220072 Minsk, Belarus.
authors.forename: Nikolaj
authors.initials: N
authors.lastname: Borisevich
authors.forename: Svetlana
authors.initials: S
authors.lastname: Loznikova
authors.forename: Aleksandr
authors.initials: A
authors.lastname: Sukhodola
authors.forename: Inessa
authors.initials: I
authors.lastname: Halets
authors.forename: Maria
authors.initials: M
authors.lastname: Bryszewska
authors.forename: Dzmitry
authors.initials: D
authors.lastname: Shcharbin
mesh_terms: D000138:Acidosis / Q000378:metabolism*; D001241:Aspirin / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008163:Luminescent Measurements; D008274:Magnesium / Q000494:pharmacology*; D008278:Magnesium Sulfate / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects; D012965:Sodium Chloride / Q000494:pharmacology; D013696:Temperature; D013917:Thrombin / Q000187:drug effects*; D013997:Time Factors; D014364:Tryptophan / Q000737:chemistry
chemical_list: D012965:Sodium Chloride; D008278:Magnesium Sulfate; D014364:Tryptophan; D013917:Thrombin; D008274:Magnesium; D001241:Aspirin