Premium
The role of nitric oxide in aspirin induced thrombolysis in vitro and the purification of aspirin activated nitric oxide synthase from human blood platelets
Author(s) -
Kahn Nighat,
Sinha Asru K
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a625-a
Subject(s) - chemistry , platelet , aspirin , fibrin , fibrinolysis , nitric oxide , biochemistry , nitric oxide synthase , plasmin , pharmacology , thrombus , enzyme , medicine , immunology , organic chemistry
Aspirin, a well‐known inhibitor of platelet aggregation is extensively used for the prevention / treatment of coronary artery disease. The inhibitory effect of the compound is reported to be mediated through the inhibition of platelet cyclooxygenase. It is currently believed that aspirin has no effect on the formed thrombus (micro aggregates of platelets embedded in fibrin mass), which results in coronary artery disease. It was found that the exposure of platelets to aspirin either in vitro (4 μM) or in vivo (volunteers ingested 150 mg aspirin) resulted in fibrinolysis of the formed “thrombus” produced by the recalcification of platelet‐rich plasma due to the production of NO in these cells by the compound. The lysis of clot in the presence of aspirin was found to be related to the fibrinolysis with simultaneous appearance of fibrin degradation products due to the generation of serine proteinase activity by NO in the assay mixture. The aspirin activated nitric oxide synthase that catalyzed the synthesis of NO in platelets was solubilized by Triton X‐100 treatment and purified to homogeneity by chromatography on DEAE cellulose and Sephadex G‐50 columns. The enzyme was found to be a single chain polypeptide with Mr 19 kDa. The treatment of human plasminogen with NO was found to directly activate the zymogen (89 kDa) to plasmin (75 kDa) with the production of preactivation peptide (14 kDa) in the absence of cofactors, or cells without the formation of cyclic GMP in the assay mixture.