Trypsin, III

Guo Z and C L Brooks III 1998. Rapid Screening of Binding Affinities Application of the A-Dynamics Method to a Trypsin-Inhibitor System. Journal of the American Chemical Society 120 1920-1921. 

Trypsin inhibitors in cucumber were first found in a study by Walker-Simmons et /. " after wounding of leaves and treatment with proteinase inhibitor-inducing factor (PIIF). The amino acid sequence of two inhibitors isolated from Cucurhita maxima (winter squash) were determined by Wilusz et at The peptides named ITD I and ITD 111 each comprised a 29-residue sequence with six cysteine residues. The only difference between the two peptides is in position 9, which is lysine in ITD I and glutamic acid in ITD III. The reactive site is located at the peptide bond between Arg5 and Ile6. Owing to their discovery and distribution in Cucurbitaceae the inhibitor family has been named squash inhibitors. Since the initial discoveries many other members of the squash family have been found. 

The classical pathway may be activated immunologically by antigen-antibody complexes and aggregated immunoglobulins, and non-immunologically by a number of chemically diverse substances, including DNA, C-reactive protein. Staphylococcal protein A, trypsin-like enzymes and certain cellular membranes (Table III). 

Table III also contains data for a glycopeptide obtained after repeated trypsin digestion of desialyzed BSM, fractionation on Sephadex...

Table III. Molar Composition of Core Protein (Peptide) of BSM, Trypsin and /3-Elim. Glycopeptides (Pro = 3)...

At present, the binary water-soluble preparation of heparin and proteolytic enzymes is being applied for the treatment of thromboses. For instance, injection into the bloodstream of heparin-plasmin complex or a heparin-plasmin-streptokinase preparation leads to the total dissolution of the thrombus, while if introduced separately, heparin and streptokinase do not display the lytic action at all, and plasmin, alone or together with streptokinase, dissolves the thrombus only partially 132>. The treatment of acute thrombophlebitis with trypsin resulted in a full dissolution of the thrombus and in an increase of antithrombin III in the blood 133). Administration of trypsin together with heparin has an effect similar in efficiency to the action of the heparin-plasmin complex 134>. The use of a mix of heparin and urokinase for improving tbrom-boresistance of polymeric materials was also described 13S). These substances were immobilized by preliminary coating of the surface of a polymer with a graphite layer and subsequent adsorption of heparin and the enzyme. 

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