A Form of Bovine Factor X with a Single Polypeptide Chain

Mattock, P.; Esnouf, M. P.

doi:10.1038/newbio242090a0

Cited by 26 publications

(11 citation statements)

References 6 publications

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“…Thus, limited proteolysis of a singlechain factor X in vivo or during its isolation may have resulted in the formation of a two-chain structure. This hypothesis is further supported by the recent publication of Mattock and Esnouf which reported the presence of single-chain factor X in bovine plasma (9). Further experiments are required to clarify these observations, however, since the single-chain component was not activated by Russell's viper venom or by the extrinsic clotting system (28).…”

Section: Resultssupporting

confidence: 66%

See 1 more Smart Citation

A Comparison of Bovine Prothrombin, Factor IX (Christmas Factor), and Factor X (Stuart Factor)

Fujikawa

Coan

Enfield

et al. 1974

Proc. Natl. Acad. Sci. U.S.A.

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A comparison has been made of the electrophoretic behavior, chemical composition, aminoterminal sequence, and immunological properties of bovine prothrombin, factor IX (Christmas factor), and factor X (Stuart factor). Some immunological crossreactivity was found between the antibody to prothrombin and factor X although prothrombin and factor X differ substantially in amino-acid and carbohydrate composition. Considerable amino-acid sequence homology was found in the amino-terminal portion of prothrombin, factor IX, and the light chain of factor X. These data provide further evidence to support the hypothesis that at least three of the vitamin K-dependent clotting factors have evolved from a common ancestral gene.Prothrombin, factor IX (Christmas factor), and factor X (Stuart factor) are three of the four coagulation factors that require vitamin K for their biosynthesis (1). Prothrombin and factor X have molecular weights of 70,000 (2) and 55,000 (3-5), respectively. Prothrombin is composed of a single polypeptide chain (6-8), while factor X contains a heavy and a light chain (3,5). A recent report suggests that factor X may also be present as a single polypeptide chain (9). Factor IX has a molecular weight of 55,400 and consists of a single polypeptide chain (10). All three coagulation factors are glycoproteins.During blood coagulation, factor IX, factor X, and prothrombin are converted to enzymes in a series of stepwise reactions (1). These enzymes then participate in coagulation as proteases of different protein substrate specificities. Thrombin and factor Xa (activated factor X) are serine esterases that are homologous in the amino-terminal and active-site regions of their heavy (or B) chains (11).In the present communication, we compare some of the physical and chemical properties of prothrombin, factor IX, and factor X and show that the amino-terminal sequences of all three proteins are homologous. MATERIALS AND METHODSBovine factor X1 and the light chain of factor X1 were prepared according to the method of Fujikawa et al. (3). BovineThe nomenclature for various coagulation factors is that recommended by an international nomenclature committee [Wright, I. (1959) Hermodson et al. (21). In the quantitation of the terminal residues, protein concentration was determined in an amino-acid analyzer on a separate aliquot after hydrolysis. Norleucine was used as an internal standard to calculate protein recovery. Antisera to factor IX and to prothrombin were prepared by methods described for factor X (3). The protein concentrations of the antisera were 12 mg/ml for the antiserum against prothrombin, 8.0 mg/ml for antiserum against factor IX, and 8.5 mg/ml for antiserum against factor X. Assays for factors IX and X and prothrombin were carried out as described (3, 10). RESULTS AND DISCUSSIONDisc-gel electrophoresis and zone electrophoresis patterns for prothrombin, factor IX, and factor X are shown in Figs. 1 and 2. Single sharp bands or spots are obtained for each of these proteins by both procedures. Und...

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Section: Resultssupporting

confidence: 66%

“…Prothrombin is composed of a single polypeptide chain (6-8), while factor X contains a heavy and a light chain (3,5). A recent report suggests that factor X may also be present as a single polypeptide chain (9). Factor IX has a molecular weight of 55,400 and consists of a single polypeptide chain (10).…”

Section: Introductionmentioning

confidence: 99%

A Comparison of Bovine Prothrombin, Factor IX (Christmas Factor), and Factor X (Stuart Factor)

Fujikawa

Coan

Enfield

et al. 1974

Proc. Natl. Acad. Sci. U.S.A.

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“…In 1977, Prowse and Esnouf (4) identified an additional vitamin K-dependent protein circulating in bovine plasma and named it protein Z (PZ). Initially thought to represent a single-chain form of bovine factor X, bovine PZ was later identified as a discrete Glacontaining protein (5,6). The human counterpart of bovine PZ was isolated in 1984 (7).…”

mentioning

confidence: 99%

Isolation of a protein Z-dependent plasma protease inhibitor

Han

Fiehler

Broze

1998

Proc. Natl. Acad. Sci. U.S.A.

142

185

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Human protein Z (PZ) is a 62,000-M r , vitamin K-dependent plasma protein whose structure is similar to coagulation factors VII, IX, X, protein C, and protein S, but whose function is not known. The procoagulant activity of factor Xa in a one-stage plasma coagulation assay is reduced when factor Xa is first incubated with PZ. This apparent inhibitory effect is time dependent, requires the presence of calcium ions and procoagulant phospholipids (rabbit brain cephalin), and appears predominantly related to the incubation period of PZ with cephalin. In serum the initial rate of inhibition of factor Xa with calcium ions and cephalin also is enhanced in the presence PZ. A PZ-dependent protease inhibitor (ZPI) has been isolated from plasma. ZPI is a 72,000-M r single-chain protein with an N-terminal amino acid sequence of LAPSPQSPEXXA (X ‫؍‬ indeterminate) and an estimated concentration in citrate-treated plasma of 1.0-1.6 g͞ml. In systems using purified components, the factor Xa inhibition produced by ZPI is rapid (>95% within 1 min by coagulation assay) and requires the presence of PZ, calcium ions, and cephalin. The inhibitory process appears to involve the formation of a factor Xa-PZ-ZPI complex at the phospholipid surface.Vitamin K is required for the posttranslational formation of ␥-carboxyglutamic acid (Gla), which is present in a number of plasma proteins that are involved in coagulation: prothrombin, factors VII, IX, and X, protein C, and protein S (1, 2). Gla-mediated calcium ion binding in these proteins is necessary for their association with phospholipid surfaces and is critical for their hemostatic function (3). In 1977, Prowse and Esnouf (4) identified an additional vitamin K-dependent protein circulating in bovine plasma and named it protein Z (PZ). Initially thought to represent a single-chain form of bovine factor X, bovine PZ was later identified as a discrete Glacontaining protein (5, 6). The human counterpart of bovine PZ was isolated in 1984 (7).Human PZ is a 62,000-M r glycoprotein that has a plasma half-life of Ϸ2.5 days (8). Plasma PZ levels in blood donors span a broad range with a mean concentration of 2.9 Ϯ 1.0 g͞ml in EDTA-anticoagulated samples (corresponding to Ϸ2.6 g͞ml in citrated plasma) (8). The N-terminal half of PZ is very homologous to those of factors VII, IX, and X, and contains a Gla-domain, two epidermal growth factor-like domains, and a region that connects to a homologue of the catalytic domains present in the serine protease zymogens. In the C-terminal domain of PZ, however, the region around the typical ''activation'' site is absent and the His and Ser residues of the catalytic triad are lacking (the Asp residue is conserved) (9, 10).McDonald et al. (11) recently reported that the kinetics of the binding of human and bovine PZ to phosphatidylcholine͞ phosphatidylserine (75%͞25%) vesicles is different from that of the other vitamin K-dependent coagulation factors. The k assn (10) and k dssn (s Ϫ1 ) rate constants are 1.95 and 0.0063 for bovine PZ and 3.36 and 0.057 ...

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“…Recently Prowse and Esnouf described another vitamin K-dependent protein in bovine plasma and they named it Protein Z (4). Initially this protein was thought to represent a form of Factor X (single chain), but it was later identified as a discrete gamma carboxyglutamic acid-containing protein (5,6). The physiological function of bovine Protein Z remains unknown.…”

Section: Introductionmentioning

confidence: 99%

Human Protein Z.

Broze¹,

Miletich²

1984

J. Clin. Invest.

140

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A s bstract. Protein Z was purified from human plasma by a four-step procedure which included barium citrate adsorption, ammonium sulfate fractionation, DEAE-Sepharose chromatography, and blue agarose chromatography with a yield of 20%. It is a 62,000 mol wt protein with an extinction coefficient of 12.0. The concentration of Protein Z in pooled, citrated plasma is 2.2 ug/ml and its half-life in patients starting warfarin anticoagulation therapy is estimated to be <2.5 d. The NH2-terminal sequence is Ala-Gly-Ser-Tyr-Leu-Leu-(Gla)-(Gla)-Leu-Phe-(Gla)-Gly-Asn-Leu. Neither Protein Z nor its cleavage products, which were obtained by treatment ofProtein Z with thrombin or plasmin, incorporated [3H]diisopropyl fluorophosphate. The physiological function of Protein Z remains unknown.

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A Form of Bovine Factor X with a Single Polypeptide Chain

Cited by 26 publications

References 6 publications

A Comparison of Bovine Prothrombin, Factor IX (Christmas Factor), and Factor X (Stuart Factor)

A Comparison of Bovine Prothrombin, Factor IX (Christmas Factor), and Factor X (Stuart Factor)

Isolation of a protein Z-dependent plasma protease inhibitor

Human Protein Z.

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