Discovery and development of direct thrombin inhibitors the binding site for the globular amino-terminal domain and exosite 1 is the binding site for the acidic carboxy-terminal domain of hirudin. Native hirudin, a 65-amino-acid polypeptide, is produced in the parapharyngeal glands of medicinal leeches. Hirudins today are produced by recombinant biotechnology using yeast. These recombinant hirudins lack a sulfate group at Tyr-63 and are therefore called desulfatohirudins. They have a 10-fold lower binding affinity to thrombin compared to native hirudin, but remain a highly specific inhibitor of thrombin and have an inhibition constant for thrombin in the picomolar range. Renal clearance and degradation account for the most part
Venoms in medicine pharmacology) or target directed assays to identify their biological target and mechanism of action (reverse pharmacology). In this way, toxic venomous poisons may be a starting point for a therapeutic drug. Venoms are naturally occurring substances that organisms evolved to deploy against other organisms, in defense or attack. They are often mixtures of proteins that act together or singly to attack their specific targets within the organism against which they are used, generally with high specificity and generally easily accessible through the vascular system. This has made venoms a subject of study for people who work in drug discovery. With