Activation of factor IX by factor XIa: A spectrophotometric assay for factor IX in human plasma

G. Tans; T. Janssen-Claesssen; G. van Dieijen; H.C. Hemker; J. Rosing

doi:10.1055/s-0038-1657240

Activation of factor IX by factor XIa: A spectrophotometric assay for factor IX in human plasma

G. Tans, T. Janssen-Claesssen, G. van Dieijen, H.C. Hemker, J. Rosing

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Abstract

The activation of Factor IX by partially purified Factor XIa was followed by active site titration, gelelectrophoresis and by a spectrophotometric assay. The assay is based on the finding that the rate of Factor X activation in the presence of phospholipid and Ca2+ is linear in time and proportional to the amount of Factor IXa present and can be determined with the chromogenic substrate S2222. Conditions were found that allowed complete activation of Factor IX in human plasma by Factor XIa. The amount of Factor IXa present in the plasma sample can be determined with the spectrophotometric assay and is proportional with the amount of plasma present. In plasma from patients receiving vitamin-K antagonists reduced Factor IX activity is found with the spectrophotometric assay, and the new assay method may be useful in monitoring oral anticoagulant therapy.

Original language	English
Pages (from-to)	127-132
Number of pages	6
Journal	Thrombosis and Haemostasis
Volume	48
Issue number	2
DOIs	https://doi.org/10.1055/s-0038-1657240
Publication status	Published - 1982

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title = "Activation of factor IX by factor XIa: A spectrophotometric assay for factor IX in human plasma",

abstract = "The activation of Factor IX by partially purified Factor XIa was followed by active site titration, gelelectrophoresis and by a spectrophotometric assay. The assay is based on the finding that the rate of Factor X activation in the presence of phospholipid and Ca2+ is linear in time and proportional to the amount of Factor IXa present and can be determined with the chromogenic substrate S2222. Conditions were found that allowed complete activation of Factor IX in human plasma by Factor XIa. The amount of Factor IXa present in the plasma sample can be determined with the spectrophotometric assay and is proportional with the amount of plasma present. In plasma from patients receiving vitamin-K antagonists reduced Factor IX activity is found with the spectrophotometric assay, and the new assay method may be useful in monitoring oral anticoagulant therapy.",

author = "G. Tans and T. Janssen-Claesssen and {van Dieijen}, G. and H.C. Hemker and J. Rosing",

year = "1982",

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journal = "Thrombosis and Haemostasis",

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T1 - Activation of factor IX by factor XIa

T2 - A spectrophotometric assay for factor IX in human plasma

AU - Tans, G.

AU - Janssen-Claesssen, T.

AU - van Dieijen, G.

AU - Hemker, H.C.

AU - Rosing, J.

PY - 1982

Y1 - 1982

N2 - The activation of Factor IX by partially purified Factor XIa was followed by active site titration, gelelectrophoresis and by a spectrophotometric assay. The assay is based on the finding that the rate of Factor X activation in the presence of phospholipid and Ca2+ is linear in time and proportional to the amount of Factor IXa present and can be determined with the chromogenic substrate S2222. Conditions were found that allowed complete activation of Factor IX in human plasma by Factor XIa. The amount of Factor IXa present in the plasma sample can be determined with the spectrophotometric assay and is proportional with the amount of plasma present. In plasma from patients receiving vitamin-K antagonists reduced Factor IX activity is found with the spectrophotometric assay, and the new assay method may be useful in monitoring oral anticoagulant therapy.

AB - The activation of Factor IX by partially purified Factor XIa was followed by active site titration, gelelectrophoresis and by a spectrophotometric assay. The assay is based on the finding that the rate of Factor X activation in the presence of phospholipid and Ca2+ is linear in time and proportional to the amount of Factor IXa present and can be determined with the chromogenic substrate S2222. Conditions were found that allowed complete activation of Factor IX in human plasma by Factor XIa. The amount of Factor IXa present in the plasma sample can be determined with the spectrophotometric assay and is proportional with the amount of plasma present. In plasma from patients receiving vitamin-K antagonists reduced Factor IX activity is found with the spectrophotometric assay, and the new assay method may be useful in monitoring oral anticoagulant therapy.

U2 - 10.1055/s-0038-1657240

DO - 10.1055/s-0038-1657240

M3 - Article

SN - 0340-6245

VL - 48

SP - 127

EP - 132

JO - Thrombosis and Haemostasis

JF - Thrombosis and Haemostasis

IS - 2

ER -