Characteristics and lipid requirements of coagulant proteins extracted from lung and brain: the specificity of the protein component of tissue factor

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Abstract

Soluble proteins were prepared from bovine lung and brain which, when combined with phospholipids, had the biological characteristics of tissue factor. The proteins were solubilized from delipidated (heptane; butanol-extracted) acetone powders with deoxycholate, and precipitated by (NH4)2SO4 (30-60% saturation). These soluble proteins, which contained less than 1% phospholipid, were essentially inert in an assay for tissue factor. When they were recombined with phospholipids, however, activity increased by a factor of 500-1000. Phosphatidylethanolamine was the most active specific phospholipid, followed by phosphatidylcholine. Phosphatidylserine was inert. Mixed phospholipids were from two to four times more active than phosphatidylethanolamine. Maximum activity was obtained at phospholipid to protein ratios of 1.5:1 (wt/wt), and when relipidation was performed in deoxycholate followed by dialysis against 0.05 M imidazole-0.375 M NaCl, pH 7.2.

Authors

Yale Nemerson