Thromb Haemost 1994; 71(01): 062-067
DOI: 10.1055/s-0038-1642385
Review Article
Schattauer GmbH Stuttgart

Characterization of a Monoclonal Antibody Directed Against the Carboxyl-Terminus of Human Factor XIII

An Epitope Exposed Upon Denaturation and Conserved Across Species Lines
Yeqing Song
The Department of Molecular Biology, Princeton University and Macromolecular Biochemistry, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, NJ, USA
,
Stephen M Taubenfeld
The Department of Molecular Biology, Princeton University and Macromolecular Biochemistry, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, NJ, USA
,
DeQuan Sheng
The Department of Molecular Biology, Princeton University and Macromolecular Biochemistry, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, NJ, USA
,
Gary R Matsueda
The Department of Molecular Biology, Princeton University and Macromolecular Biochemistry, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, NJ, USA
› Author Affiliations
Further Information

Publication History

Received: 09 June 1993

Accepted after revision 23 September 1993

Publication Date:
12 July 2018 (online)

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Summary

By deriving an anti-peptide monoclonal antibody, mAb 7A4, we characterized the relatively unstudied carboxyl-terminal end of the α-chain of human factor XIII, the plasma transglutaminase. MAb 7A4 was directed against the last eight amino acids (Gln-Ile-Gln-Arg-Arg-Pro-Ser-Met) and bound with a dissociation constant of 3.4 × 10−8 M. In a solid assay format, mAb 7A4 bound equally well to factor XIII obtained from human plasma, platelets or placenta. However, in a solution-phase assay format, the epitope was largely unavailable but could be readily exposed by heat denaturation. Tmmunoblotting showed that this epitope is conserved among all species of plasma factor XIII tested except rabbit suggesting that the carboxyl-terminus might be an important structural element. Other competitive binding experiments with synthetic peptides as inhibitors pointed toward the final carboxyl-terminal amino acid, Met-731, as an immunochemically important determinant. This was used advantageously to confirm the finding that the caiboxyl-leiminal Mel-731 is largely absent from placental factor XIII (1) as compared to platelet or plasma factor XIII.