Practical Protein Chemistry - A. Darbre 1989

Analytical Methods
Introduction

A. DARBRE (Department of Biochemistry, King’s College London, Strand, London WC2R 2LS, U.K.), with the participation of J. R. CLAMP (Department of Medicine, Medical School, University of Bristol, University Walk, Bristol BS8 1TD, U.K.)

This chapter examines analytical techniques that have found widespread application in Protein Chemistry (provided they are not discussed elsewhere in the book). The uninitiated reader might feel that an excessive number of alternative Methods are presented here, and that in certain cases a single method would have sufficed. The author acknowledges the validity of such potential criticism, yet emphasizes that no single method is universally applicable to all Proteins. This is because, on the one hand, The Nature of the test subjects and their quantitative availability vary greatly; on the other hand, protein research laboratories differ dramatically in their equipment, availability of Reagents, and other technical resources. To keep the material within manageable limits, some methods—such as isotachophoresis and chromatofocusing—are not discussed.

Structure/149.html">The problem of sample contamination by foreign impurities is acquiring ever-greater significance in protein chemistry, as analytical sensitivity increases and researchers frequently have to deal with minute quantities of substances. It has been demonstrated that sources of contamination in gas-liquid chromatographic Amino acid analysis can include fingerprints, dirty glassware, Water, Hydrochloric acid, rubber gloves, and more obvious contaminants such as saliva, Skin flakes, and cigarette smoke [310]. More than 150 Peptides have been detected in a single fingerprint [242] (Sec. 8.19.2.2).

It is quite likely that in the future, the application of highly sensitive amino acid analysis methods (at sub-picomole levels) will necessitate the preparation of all Reagent and Buffer solutions, as well as all protein Separation Procedures, under aseptic conditions. However, current requirements primarily concern glassware, water, and reagents, which must be of the highest purity.