Partial purification and characterization of extrinsic pathway inhibitor (the factor Xa-dependent plasma inhibitor of factor VIIa/tissue factor).

Thrombosis research. 1987;48(1):11-22

Plain language summary

Green tea (GT) consumption has been associated with the prevention and control of type 2 diabetes, cardiovascular and metabolic disease as well as having a positive effect on body weight and composition. However, the polyphenols in GT have been shown to interact with mineral distribution within the body and those minerals have been shown to be deficient in obesity. Studies to measure mineral status in obese subjects supplementing with GT have been inconclusive and this study aimed to measure the serum concentrations of minerals (calcium, copper, iron, zinc, magnesium), body mass index, total antioxidant status (TAS), lipid profile and glucose concentration. 46 obese patients were randomised into 2 groups, one group were supplemented with 279mg of green tea extract (GTE) and 208mg of the polyphenol epigallocatechin-3-gallate (EGCG) and the other group were issued with a placebo for 3 months. The study concluded that GTE improved Zn and Mg, however decreased levels of FE. The results confirmed a positive effect on body mass, lipid profile, glucose and TAS. It was concluded that more studies are required on a larger population over a longer period of time.


We report a procedure to purify partially from plasma (approximately 1200 fold) the factor Xa-dependent inhibitor of factor VIIa/tissue factor (i.e., the extrinsic pathway inhibitor or EPI) and describe some of its properties. An assay for EPI was developed based upon inhibition of factor VIIa/tissue factor induced release of activation peptide from tritiated factor IX by a test sample in the presence but not in the absence of factor Xa. Approximately 50% of the total EPI activity in plasma was found in the lipoprotein fraction, which was used as the starting material for purification. Total lipoproteins (isolated by density ultracentrifugation) were delipidated and the urea soluble apoproteins gel filtered on Sephacryl S-200. The inhibitory activity co-eluted with the major protein peak, which primarily contained apoprotein A-I. Inhibitory activity was separated from apoprotein A-I by anion-exchange chromatography on Q-Sepharose and was further resolved from higher and lower molecular weight contaminating proteins by polypreparative disc gel electrophoresis in the presence of 0.1% SDS. Functional inhibitory activity eluted from the polypreparative disc gel in two discrete pools of different molecular weights (approximately 34,000 and approximately 43,000 D). Apoprotein E was identified by immunological techniques as the major protein present in both of these pools. However, incubation with a monospecific polyclonal antibody to human apoprotein E did not decrease EPI activity either in plasma or in the partially purified polypreparative disc gel fractions. A rabbit antiserum was prepared against material from the polypreparative disc gel. The IgG fraction neutralized approximately 95% of the total inhibitory activity present in plasma. Therefore, EPI in the lipoprotein fraction and in the non-lipoprotein fraction of plasma appears to be antigenically similar.

Lifestyle medicine

Fundamental Clinical Imbalances : Detoxification and biotransformational
Patient Centred Factors : Mediators/Green tea extract
Environmental Inputs : Nutrients
Personal Lifestyle Factors : Nutrition
Functional Laboratory Testing : Blood

Methodological quality

Jadad score : 4
Allocation concealment : Yes