Bill Sheffield, PhD

• Plasma Proteins
• Serpin Protease Inhibitors
• Gene-Fusion Proteins

Research in the Sheffield laboratory focuses on plasma and plasma proteins in three general ways: in efforts to extend the circulatory lifetime of recombinant plasma proteins; in work aimed at producing novel plasma proteins with either procoagulant or anticoagulant properties; and in quality monitoring of plasma and plasma products. Ongoing projects include: 1) Structure/function studies of the serine protease inhibitor (serpin) family members alpha-1-proteinase inhibitor, antithrombin, heparin cofactor II, and alpha-2-antiplasmin; 2) Fate of mutant albumin molecules in vivo in rabbits and mice, and efficacy in animal models of hemorrhage or thrombosis; 3) Gene fusion approaches to altering the clearance or distribution of plasma proteins (e.g. factors VII and VIII); and 4) Quality and efficacy of therapeutic plasma in vitro and in vivo. A variety of biochemical and molecular biological approaches are used, including site-directed and PCR-based mutagenesis of cDNAs, expression of recombinant proteins in bacterial, yeast, or cultured mammalian cell systems, protein characterisation using enzymatic, immunochemical and biochemical techniques, in vivo studies of recombinant or natural proteins or protein mixtures injected into rabbits and/or mice, and characterization of the ability of plasma to support in vitro clotting.
 

Selected Publications:

Sheffield WP, Eltringham-Smith LJ, Bhakta V, Gataiance S. A long-lasting, plasmin-activatable thrombin inhibitor aids in vitro clot lysis and does not promote bleeding in vivo. Thrombosis and Haemostasis 2009; 101: 867-77.

Sheffield WP, Eltringham-Smith LJ, Gataiance S, Bhakta V. Addition of a sequence from a2-antiplasmin transforms human serum albumin into a blood clot component that speeds clot lysis. BMC Biotechnol. 2009 Mar 3;9:15.

Sutherland JS, Bhakta V, Sheffield WP. The appended tail region of heparin cofactor II and additional reactive centre loop mutations combine to increase the reactivity and specificity of alpha-1-proteinase inhibitor M358R for thrombin. Thrombosis and Haemostasis 2007; 98: 1014-1023.

Sutherland JS, Bhakta V, Filion M, Sheffield WP. The transferable tail: Fusion of the N-terminal acidic domain of heparin cofactor II to alpha-1-proteinase inhibitor M358R specifically increases the rate of thrombin inhibition. Biochemistry 2006; 45:11444-52.

Sheffield WP, Wilson B, Eltringham-Smith LJ, Gataiance S, Bhakta V. Superior inhibition of human but not rabbit platelet aggregation by a barbourin-albumin fusion protein compared to recombinant albumins with short amino-terminal extensions. Thromb Haemostas 2005; 93: 914-21.