Jeffrey W. Gross

Rapid mix-quench MALDI-TOF mass spectrometry for analysis of enzymatic systems.

Mass spectroscopy has been used as an analytical technique for several decades, but only recently, with the advent of the soft-ionization techniques matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI), has the broader application of this discipline spread into the mainstream of biological sciences. Both MALDI and ESI allow the nondestructive ionization of large molecules, and thus permit the facile analysis of a wide range of biological molecules. As a result of these advances, the past decade has witnessed an explosive growth in the novel application of mass spectrometry. These spectrometers can be used quantitatively, can provide isotopic resolution for molecules up to several thousand mass units, and can allow the accurate determination of mass values for molecules as large as several hundred thousand Daltons. Consequently, a remarkably diverse set of steady-state enzymatic reactions have been monitored by mass spectrometry. This chapter summarizes the use of MALDI-time-of-flight (TOF) mass spectrometry for the quantitative analysis of enzyme-catalyzed reactions in the pre-steady state.