Antithrombin Chicago, amino acid substitution of arginine 393 to histidine.
Antithrombin Chicago is a functionally inactive antithrombin variant whose inheritance is associated with thrombotic disease. The variant antithrombin was isolated from plasma of the propositus by chromatography on heparin-Sepharose, followed by passage through thrombin-Sepharose to remove the normal antithrombin component that is present. A pool of fragments ("CNBr pool 4") containing the reactive site region was prepared from the reduced and S-carboxymethylated variant by cleavage with cyanogen bromide followed by reverse-phase HPLC. Sequential treatment of CNBr pool 4 with trypsin and V8 protease produced peptides whose molecular masses were then determined by fast atom bombardment mass spectrometry. The variant protein digests were characterised by a reduction of a peptide of mass 1086, corresponding to the normal antithrombin sequence Ala382-Arg393. However, they contained a peptide of mass 1748, which arises when Arg393 is replaced by His in the sequence Ala382-Arg399. It is concluded that the functional and clinical abnormalities of antithrombin Chicago are all probably caused by a single amino acid substitution, Arg393 to His.
Erdjument
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H
Department of Haematology, Charing Cross and Westminster Hospital Medical School, Hammersmith, London.
Lane
D A
DA
Panico
M
M
Di Marzo
V
V
Morris
H R
HR
Bauer
K
K
Rosenberg
R D
RD
D000595:Amino Acid Sequence; D058833:Antithrombin Proteins; D000991:Antithrombins / Q000032:analysis* / Q000235:genetics; D001120:Arginine / Q000032:analysis*; D006639:Histidine / Q000032:analysis*; D006801:Humans; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009154:Mutation; D014357:Trypsin / Q000378:metabolism
D058833:Antithrombin Proteins; D000991:Antithrombins; C061168:antithrombin Chicago; D006639:Histidine; D001120:Arginine; D014357:Trypsin