Snake venom protease

Snake Venom Protease Family Crotalus adamanteus, HAG HiSa 3 HiSa 5 His H2O ... 

Metalloprotease Snake Venom Protease Family Cro talus adamanteus HISq, 3 HISq, 5 His(C) H2O 41,42... 

Figure 2.14 shows examples of both cases, an isolated ribbon and a p sheet. The isolated ribbon is illustrated by the structure of bovine trypsin inhibitor (Figure 2.14a), a small, very stable polypeptide of 58 amino acids that inhibits the activity of the digestive protease trypsin. The structure has been determined to 1.0 A resolution in the laboratory of Robert Huber in Munich, Germany, and the folding pathway of this protein is discussed in Chapter 6. Hairpin motifs as parts of a p sheet are exemplified by the structure of a snake venom, erabutoxin (Figure 2.14b), which binds to and inhibits... 

Januario AH, Simone LS, Silvana M, et al. Neo-clerodane diterpenoid, a new metallo-protease snake venom inhibitor from Baccharis trimera (Asteraceae) anti-proteolytic and anti-hemorrhagic properties. Chem Biol Interact 2002 150 243-251. 

Nerve growth factor is commonly found in snake venoms. This is a protease with specificity for lysyl and arginyl bonds, which contains one Zn2+ per molecule. The function of the zinc is to prevent the activation of NGF, presumably through control of the structure. Removal of Zn11 from NGF with EDTA leads to activation of the zymogen. 

Snake venoms have been studied extensively their effects are due, in general, to toxins that are peptides with 60 to 70 amino acids. These toxins are cardiotoxic or neurotoxic, and their effects are usually accentuated by the phospholipases, peptidases, proteases, and other enzymes present in venoms. These enzymes may affect the bloodclotting mechanisms and damage blood vessels. Snake bites are responsible for less than 10 deaths per year in the United States but many thousand worldwide. 

Protease b snake venom 16 Man, GIcNAc, Gal, Sialic acid 43... 

ADAM. A Disintesrin And MetalloProteinase family of proteins. Disintegrins, as the name implies, are proteins which interfere with interactions of cells with proteins in the extracellular matrix. An example are the inhibitors of the interaction of blood platelets with fibrinogen. Disintegrins are found in snake venom. Metalloproteinases are a family of proteases which need a bivalent cation for catalysis. MMP s are matrix metallo-proteases. They are associated with the extracellular matrix. 

Bradykinin and kallidin ate potent vasodilators and hypotensive agents that have different peptide structures bradykinin is a nonapeptide, whereas kallidin is a decapepttde. Kdlidin is ly.syl-bradykinin that is. it has an additional lysine at the NH2 terminus of the chain. Tliese two compounds arc made available from kininogen. a hlood globulin, on hydrolysis. Trypsin, plasmin, or the proteases of certain snake venoms can catalyze the hydrolysis of kininogen. 

A vasodilating peptide with smooth-muscle stimulating action was described by Rocha e Silva, Beraldo and Rosenfeld in 1949 and named bradykinin. It is produced by the action of trypsin or snake venoms on plasma. A similar substance, kallidin, was prepared shortly afterwards by Werle and Berek using the protease kalUkrein. Other peptides with similar properties have been described and the general term kinins or, when derived from plasma proteins, plasma kinins has been recommended. The best-known kinin, bradykinin, has recently been shown to be a nonapeptide, and its structure confirmed by synthesis - . When injected subcutaneously into laboratory animals and man, bradykinin causes vasodilatation, increased vascular permeability, leucocyte infiltration and pain. 

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