Snake Venom Proteins Affecting Platelets and Their Applications to Anti-Thrombotic Research

Abstract

Snake venoms are very complex mixtures of biologically active proteins and peptides that may affect hemostasis in many ways, by activating or inhibiting coagulant factors or platelets, or by disrupting endothelium. They have been classified into various families, including serine proteases, metalloproteinases, C-type lectins, disintegrins and phospholipases. The various members of a particular family act selectively on different blood coagulation factors, blood cells or tissues. Venom proteins affect platelet function in particular by binding to and blocking or clustering and activating receptors or by cleaving receptors or von Willebrand factor. They may also activate protease-activated receptors or modulate ADP release or thromboxane A2 formation. L-amino acid oxidases activate platelets by producing H2O2. Many of these purified components are valuable tools in platelet research, providing new information about receptor function and signaling.

Fibrinolytic Enzymes from Medicinal Mushrooms

“…These biological molecules have been classified as serine proteases, metalloproteinases, C-type lectins, disintegrins and phospholipases. Each may act selectively on different blood coagulation factors, blood cells, and tissues (Clemetson et al, 2007). Venom proteases may involve activation or inactivation of each factor related to coagulation and fibrinolysis.…”

Overlooked Issues of Snakebite Management: Time for Strategic Approach

“…Disintegrins, C-type lectins, and phospholipases also affect haemostasis. There are a good number of articles and reviews devoted much to understand the molecular structure-function relationships of systemic toxins and of course to a lesser extent the neutralization of systemic toxicity by the anti-venom therapy [3][4][33][34][35]. Therefore, the main focus of the present review is to address on the neglected issues of snakebite and its management including local toxicity, limitations of existing therapy, and the possible long-term complications of snakebite.…”

CHAPTER 5. Reptile Venoms as a Platform for Drug Development

“…These low molecular weight proteins were rst discovered from the venoms of vipers in the late 1980s and were shown to be potent inhibitors of platelet aggregation. 67 Since then, over 50 different disintegrins have been puried from snake venoms, 68 and they are classied into three functional groups according to their integrin selectivity and their bioactive tripeptide motifs. 69 They have an Arg-Gly-Asp (RGD) tripeptide motif on a loop structure and interfere in the nal common step of platelet aggregation in which the integrin a IIB b 3 receptor binds to the RGD motif present on target proteins such as brinogen, bronectin, vitronectin and vWF.…”