Formation of a covalent disulfide-linked antithrombin-albumin complex by an antithrombin variant, antithrombin "Northwick Park".
Antithrombin is a major proteinase inhibitor of the blood coagulation system. Its inherited deficiency or abnormality is often associated with thromboembolism. Antithrombin "Northwick Park," a functionally inactive variant antithrombin, has recently been shown by us (Lane, D.A., Flynn, A., Ireland, H., Erdjument, H., Samson, D., Howarth, D., and Thompson, E. (1987) Br. J. Haematol. 65,451-456) to be present in plasma, in part, as a high Mr (approximately 120,000) component which has a characteristic electrophoretic mobility in agarose gels in the absence of denaturing agents. In this communication, we present evidence that this Mr approximately 120,000 variant component is comprised of an antithrombin-albumin covalent disulfide-linked complex. This proposal is supported by results of: (a) fast atom bombardment mass spectrometry of the isolated reduced, S-carboxymethylated, trypsin-digested Mr approximately 120,000 complex; (b) sodium dodecyl sulfate-polyacrylamide gel electrophoresis of this complex and its reduced and S-carboxymethylated constituents; (c) immunoblotting of these polyacrylamide gels with antisera specific for antithrombin and albumin; (d) NH2-terminal sequence analysis of one of the isolated, S-carboxymethylated proteins that comprise the Mr approximately 120,000 complex; and (e) fast atom bombardment mass spectrometry of its tryptic peptides.
Erdjument
H
H
Department of Haematology, Charing Cross and Westminster Medical School, Hammersmith, London, United Kingdom.
Lane
D A
DA
Ireland
H
H
Panico
M
M
Di Marzo
V
V
Blench
I
I
Morris
H R
HR
D000990:Antithrombin III / Q000235:genetics / Q000378:metabolism*; D000991:Antithrombins / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004220:Disulfides / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D014644:Genetic Variation; D006801:Humans; D008970:Molecular Weight; D010446:Peptide Fragments / Q000032:analysis; D010449:Peptide Mapping; D012709:Serum Albumin / Q000378:metabolism*
D000991:Antithrombins; D004220:Disulfides; D010446:Peptide Fragments; D012709:Serum Albumin; C046707:antithrombin III Northwick Park; D000990:Antithrombin III