Following enzyme catalysis in real-time inside a fast atom bombardment mass spectrometer

Abstract

Experiments involving the monitoring of enzyme catalyzed reactions occurring within a fast atom bombardment mass spectrometer are reported. Data are presented using FAB mass spectrometry to monitor trypsin and dipeptidyl aminopeptidase I catalyzed hydrolysis of their respective assay substrates and for hydrolysis of the peptide (val4) angiotensin III by yeast carboxypeptidase Y. Enzyme catalysis was followed by measuring the decrease of abundance of the [M + H]+ ion of the substrate and the increase of that of the product from a mixture of enzyme and substrate in a glycerol/water matrix placed on the probe inside the mass spectrometer. In addition, results of preliminary experiments to determine the survival of live yeast cells on exposure to FAB mass spectrometry is also presented.