Biological Recognition

As nature evolved, life forms had to develop a protective mechanism against invading microorganisms if they were to survive. Thus there is a constant battle between the cell's defence mechanism and the attacking microorganisms, a battle resolved by the cells generating antibodies (the immunoglobulins) able to recognize the protein coat of attacking microorganisms and signal killer cells to destroy the invaders before they cause harm to the host. Equally, if microorganisms were to survive, they had continually to mutate and change their protein coats to avoid detection by existing antibodies. The 'attack and destroy' process is a function of changes in the molecular structure in a specific part of the protein, with only the most minute of changes occurring at the surface of the protein. Evolution has thus designed a system where every protein has a very precise structure, but one which will always be recognized by another. One element of the interacting pair can be covalently bonded onto an inert matrix. The resulting chromato-graphic medium can then be packed into a column, and used to separate exclusively its matching partner from an impure mixture when added as a solution to the top of the column. This fact can be stated as follows - for every protein separation problem there is always an affinity solution. The process of producing a satisfactory medium is quite difficult.

The matching pair must be identified, and one of them isolated in a pure form. Covalent bonding onto an inert matrix in a stable manner must always allow the 'docking' surface of the protein to be positioned to make it available to the target protein. The whole also has to be achieved at an acceptable cost.

This technique has resulted in many successful applications, often using antibodies as the affinity medium (immunoaffinity chromatography), but large scale separations using these 'natural' ligands are largely restricted by cost and regulatory reasons. Although immunoaffinity chromatography is still widely practised, in recent years the evolution of design technologies has provided powerful new approaches to mimic protein structures, resulting in the development of synthetic ligands able to work in harsh operational environments and at low cost.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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