title: Fibrinogen Bergamo I (A alpha 16Arg----Cys): susceptibility towards thrombin following aminoethylation, methylation or carboxamidomethylation of cysteine residues.
abstract: An abnormal fibrinogen, denoted as "fibrinogen Bergamo I", has been characterized. Its defect consists in an exchange of arginine by cysteine in position 16 of the A alpha-chain, thus corresponding to that found in a number of other fibrinogen variants. The abnormal fibrinopeptide A cannot be split off by thrombin from intact fibrinogen Bergamo I. We describe three different chemical modifications of the cysteine A alpha 16, i.e. aminoethylation, methylation and carboxamidomethylation, and their effects on the susceptibility of fibrinogen Bergamo I towards thrombin attack. S-aminoethylation of the A alpha 16Cys renders the peptide bond A alpha 16-17 cleavable by thrombin. Following methylation or carboxamidomethylation, the A alpha 19-arginyl bond becomes accessible for thrombin. The chemically modified extended fibrinopeptide A can be readily separated from the normal fibrinopeptide A by HPLC. The latter two modifications are suitable alternative procedures for detecting the molecular defect A alpha 16Arg----Cys of fibrinogen.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D001388:Aziridines; D001778:Blood Coagulation Disorders / Q000097:blood* / Q000235:genetics; D001780:Blood Coagulation Tests; D003545:Cysteine; D005260:Female; D005340:Fibrinogen / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D015241:Fibrinogens, Abnormal; D005344:Fibrinopeptide A / Q000302:isolation & purification / Q000378:metabolism; D005345:Fibrinopeptide B / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D008297:Male; D008623:Mercaptoethanol; D008745:Methylation; D013917:Thrombin / Q000494:pharmacology*
chemical_list: D000596:Amino Acids; D001388:Aziridines; C040461:Fibrinogen Schwarzach; D015241:Fibrinogens, Abnormal; D005344:Fibrinopeptide A; D005345:Fibrinopeptide B; C033132:aziridine; D008623:Mercaptoethanol; D005340:Fibrinogen; D013917:Thrombin; D003545:Cysteine