SNAKE-VENOM METALLOPROTEINASES AND DISINTEGRINS - INTERACTIONS WITH CELLS

Metalloproteinases and disintegrins are important components of most v iperid and crotalid venoms. Large metalloproteinases referred to as MD C enzymes are composed of an N-terminalMetalloproteinase domain, a Dis integrin-like domain and a Cys-rich C-terminus. In contrast, disintegr ins are small non-enzymatic RGD-containing cysteine-rich polypeptides. However, the disintegrin region of MDC enzymes bears a high degree of structural homology to that of the disintegrins, although it lacks th e RGD motif. Despite these differences, both components share the prop erty of being able to recognize integrin cell surface receptors and th ereby to inhibit integrin-dependent cell reactions. Recently, several membrane-bound MDC enzymes, closely related to soluble venom MDC enzym es, have been described in mammalian cells. This group of membrane-anc hored mammalian enzymes is also called the ADAM family of proteins due to the structure revealing. A Disintegrin And Metalloproteinase domai ns. ADAMs are involved in the shedding of molecules from the cell surf ace, a property which is also shared by some venom MDC enzymes.