Proteins blood-clotting, 214 brain

The physiological role of vitamin K is in blood clotting and is essential for the synthesis of at least four of the proteins (including prothrombin) involved in this process. Vitamin K also plays a role in the synthesis of a protein (osteocalcin) in bone. Vitamin K deficiency is rare but can result from impaired absorption of fat. Vitamin K levels in the body are also reduced if the intestinal flora is killed (e.g. by antibiotics). Vitamin K toxicity is rare but can be caused by excessive intake of vitamin K supplements. Symptoms include erythrocyte haemolysis, jaundice, brain damage and reduced effectiveness of anticoagulants. 

Two proteins, tissue plasminogen activator (TPA) and entero-kinase (EK), are known to dissolve blood clots. If they are injected into the body within a critical period after a heart attack or stroke, either of these two proteins can prevent or minimize the disastrous effects of blood clots in the heart or brain. Without genetic recombination, enough of these proteins would never be available for this treatment to be of practical use. Currently, two different companies are producing the two proteins. 

The plaques of Alzheimer s disease and the fibrous state of the prions of mad cow disease (both with resulting brain destruction), the thrombi of stroke (cerebral thrombosis) and of heart attack (myocardial infarction), and the familiar manifestation of death (rigor mortis) represent excursions too far in the direction of protein insolubility. The favorable actions of antioxidants keep proteins from becoming so soluble (unfolded) that protein function disappears and proteolytic degradation ensues. Of course, the lack of blood clotting, hemophilia (the lack of clotting proteins to become insoluble by association of oil-like domains), results in death. Such devastations result from loss of proper balance between solubility and insolubility. They represent excursions too far from the cusp of insolubility, that is, too far from the boundary between insolubility and solubility. 

FFeart disease, particularly clogged blood vessels, is also treated with recombinant products. Alteplase (Activase ), a human recombinant protein that breaks down fibrin, is used immediately after a stroke or heart attack to break down platelet-trapping clots in small blood vessels of the heart or brain and thus improve the patient s chances for recovery. Purified enzymes from bacteria are used for the same purposes. Abciximab (ReoPro ), a monoclonal antibody to... 

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