Complex sentence: Tissue factor, also called platelet tissue factor, factor III, thromboplastin, or CD142 is a protein encoded by the F3 gene present in subendothelial tissue and leukocytes necessary for the initiation of thrombin formation from the zymogen prothrombin.
Split into simpler sentences: Tissue factor, also called platelet tissue factor, factor III, thromboplastin, or CD142 is a protein encoded by the F3 gene present in subendothelial tissue and leukocytes. It's role in the clotting process is the initiation of thrombin formation from the zymogen prothrombin.