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
Anatoxin-a(S) toxin's other poisoning symptoms which include lacrimation, urinary incontinence and defecation. Atropine will not, however, counter another mechanism of the compounds toxicity as it also mediates a nicotinic adverse toxicity affecting muscle tremors, fasciculation, convulsions and respiratory failure. Anatoxin-a(S) Anatoxin-a(S) "Salivary" is a naturally occurring cyanotoxin commonly isolated from cyanobacteria (specifically of the genus "Anabaena") and causes excess salivation in mammals via inhibition of acetylcholinesterase. Anatoxin-a(S) is structurally a cyclic "N"-hydroxyguanine organophosphate with a phosphate ester moiety. The main mechanism of action for anatoxin-a(S) is by irreversibly inhibiting the active site of acetylcholinesterase leading to excess acetylcholine in the parasympathetic