Protein chemistry combined methods

The history of protein chemistry can be summarised as improved purification techniques combined with new methods of protein characterisation allied to theoretical interpretation of the results obtained. Improved computational techniques have also helped considerably. 

A method that has been the standard of choice for many years is the Lowry procedure. This method uses Cn ions along with Folin-Ciocalteau reagent, a combination of phosphomolybdic and phosphotnngstic acid complexes that react with Cn. Cn is generated from Cn by readily oxidizable protein components, such as cysteine or the phenols and indoles of tyrosine and tryptophan. Although the precise chemistry of the Lowry method remains uncertain, the Cn reaction with the Folin reagent gives intensely colored products measurable spectrophotometrically. 

Despite the availability of fast computers and efficient codes for accurate quantum chemistry calculations, it is not likely in the near future that we will be able to study chemical reactions in proteins taking all the proteins atoms into quantum mechanical calculations. Hybrid methods in which different parts of large molecular systems are treated by different theoretical levels of methods are likely to play a key role in such studies for the coming decade or more. The ONIOM method we have developed is a versatile hybrid method that allows combining different quantum mechanical methods as well as molecular mechanics method in multiple layers, some features of... 

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