Ultraviolet Absorption Spectroscopy

Four decades ago, ultraviolet absorption spectroscopy played an important and often pivotal role in studies of protein structure and function. A comprehensive discussion of the application of ultraviolet spectroscopy to the study of proteins was provided by Wetlaufer in 1962 (), which remains a valuable source of information about the technique. The subsequent vigorous growth of protein chemistry was both partially initiated and paralleled by the introduction of powerful new techniques, such as nuclear magnetic resonance, circular dichroism, Fourier-transform infrared, and fluorescence spectroscopies. The widespread use of these methods relegated UV spectroscopy to a secondary technique most often employed for simple concentration determinations or enzymatic assays, although it was still occasionally used in protein structural studies. Nevertheless, ultraviolet spectrophotometry remains a fast, accurate, quantitative, and nondestructive technique with much to offer in studies of protein folding and structural integrity. Moreover, with new instrumental and theoretical improvements, it provides some unique features that have resulted in a moderate resurgence in its use in certain applications. The omnipresence of UV absorption spectrophotometers in biochemical laboratories also suggests that the technique may be used to provide structural information when more specialized instrumentation is not readily available.