prothrombin: a protein in blood plasma that is the inactive precursor of thrombin
coagulation factor: any of the factors in the blood whose actions are essential for blood coagulation
jerusalem thorn: large shrub or shrubby tree having sharp spines and pinnate leaves with small deciduous leaflets and sweet-scented racemose yellow-orange flowers; grown as ornamentals or hedging or emergency food for livestock; tropical America but naturalized in southern United States