Proteins Recognising Carbohydrates

M. von Itzstein Carbohydrate-recognising proteins as targets for drug research J. C. Paulson Sialoside sweet spots. 

E-selectin recognises and binds to sialylated carbohydrates present on the surface proteins of certain leukocytes. The local release of cytokines IL-1 and TNF induces the overexpression of E-selectin on the endothelial cells of nearby blood vessels. Leukocytes with a low affinity for E-selectin will slow and roll along the internal surface of the vessel. 

As long ago as 1827 W. Prout had recognised three types of complex food components, which today are known as carbohydrates, fat (lipids) and proteins. It was not until much later that another component, nucleic acids, was also recognised, and that all these four components were often present in phosphorylated forms. Only in the latter part of the nineteenth century did the beneficial effects of added (often simple) phosphorns compounds start to be appreciated. Only by the middle of the twentieth century was their mass use by the food industries firmly established. 

Although complement pathways have not been extensively described in bivalves, there are several lines of evidence that support the presence of this defence mechanism in these organisms. The complement system is composed of more than 30 soluble plasma proteins that collaborate to distinguish and eliminate non-self particles. C3 is the central component system. In vertebrates, it is proteolyticaUy activated by a C3 convertase through the classic, lectins and alternative routes (Nonaka and Yoshizaki, 2004). In the classic activation route, immunoglobulins are recognised by the Cl protein, whereas activation is initiated by the recognition of membrane carbohydrates by lectins and ficolins in the lectin route (Nonaka and Kimura, 2006). 

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