S-nitrosothiols affect fibrinogen structure and function.

S-Nitrosoglutathione, (50 muM) inhibited the initial rate of thrombin-catalyzed fibrinogen polymerization by ∼80%. The fact that the same concentration of S-nitrosoglutathione had no effect on thrombin-dependent hydrolysis of tosylglycylprolylarginine-4-nitranilide acetate suggested that the nitrosothiol was affecting fibrinogen structure. This was confirmed by circular dichroism spectroscopy where S-nitrosoglutathione and S-nitrosohomocysteine increased the alpha-helical content of fibrinogen by ∼19% and 11% respectively. S-carboxymethylamido derivatives of glutathione or Hcys had no effect on the fibrinogen 2° structure. The S-nitrosothiol-dependent 2° structural effects were reversed upon gel filtration chromatography suggesting that the effects were allosteric. Further evidence for fibrinogen-S-nitrosoglutathione interactions were obtained from S-nitrosoglutathione-dependent quenching of the intrinsic fibrinogen Trp fluorescence as well as the quenching of the S-NO circular dichroic absorbance of S-nitrosoglutathione as a function of fibrinogen concentration. These studies enabled the estimation of a K D of ∼40 muM for the fibrinogen-S-nitrosoglutathione interaction with a stoichiometry of 2:1 (S-nitrosoglutathione:fibrinogen).Dept. of Chemistry and Biochemistry. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2001 .V54. Source: Masters Abstracts International, Volume: 40-03, page: 0707. Adviser: B. Mutus. Thesis (M.Sc.)--University of Windsor (Canada), 2001