title: Determination of the P1', P2' and P3' subsite-specificity of factor Xa.
abstract: Factor Xa is a central protease in the coagulation cascade and the target for many anticoagulant compounds currently under development. The preferences of the enzyme for substrates incorporating residues N-terminal to the cleavage site (P1, P2, etc.) have been elucidated, but little is known of its preferences for residues C-terminal to the cleavage site (P1', P2', etc.). The preferences of bovine factor Xa for substrate residues in the P1', P2' and P3' positions were mapped using fluorescence-quenched substrates. Bovine factor Xa, often used as a model for factor Xa, was most selective for the P2' position, less selective at the P1' position and almost completely non-selective at the P3' position. It appears that while the prime side subsites of factor Xa impose some selectivity towards substrates, the influence of these sites on factor Xa cleavage specificity is relatively low in comparison to related enzymes such as thrombin.
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, P.O. Box 13D, Clayton, Vic. 3800, Australia.
authors.forename: Justin P
authors.initials: JP
authors.lastname: Ludeman
authors.forename: Robert N
authors.initials: RN
authors.lastname: Pike
authors.forename: Karen M
authors.initials: KM
authors.lastname: Bromfield
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Duggan
authors.forename: Julia
authors.initials: J
authors.lastname: Cianci
authors.forename: Bernard
authors.initials: B
authors.lastname: Le Bonniec
authors.forename: James C
authors.initials: JC
authors.lastname: Whisstock
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Bottomley
mesh_terms: D000818:Animals; D002417:Cattle; D015951:Factor Xa / Q000737:chemistry / Q000378:metabolism*; D005453:Fluorescence; D007700:Kinetics; D019151:Peptide Library; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D019151:Peptide Library; D010455:Peptides; D015951:Factor Xa