Using electrospray ionization FTICR mass spectrometry to study competitive binding of inhibitors to carbonic anhydrase

Journal Article · Wed Aug 30 04:00:00 EDT 1995 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja00139a023· OSTI ID:102729

Cheng, X; Chen, R; Bruce, J E; Schwartz, B L; Anderson, G A; Hofstadler, S A; Gale, D C; Smith, R D ^[1]; Gao, J; Sigal, G B; Mammen, M; Whitesides, G M ^[2]

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1. Pacific Northwest Lab., Richland, WA (United States)
2. Harvard Univ., Cambridge, MA (United States)

We report a method based on mass spectrometry for the characterization of noncovalent complexes of proteins with mixtures of ligands; this method is relevant to the study of drug leads and may be useful in screening libraries for tight-binding compounds. This study describes the competitive binding of inhibitors derived from para-substituted benzenesulfonamides to bovine carbonic anhydrase II (BCAII, EC 4.2.1.1) using this technique. Relative binding constants and structural information for a mixture of inhibitors can be obtained in a single experiment using ESI-FTICR-MS. The work demonstrates that ESI-MS has significant potential for measuring relative binding affinities and characterizing the structures of ligands associated noncovalently to proteins. We have detected noncovalent complexes in the gas phase for ligands having values of K{sub b} as low as 1.7 x 10{sup 6} M{sup -1} in solution. The technique also allowed identification of tightbinding ligands from small libraries. The structures of inhibitors having similar masses can be identified by the high-resolution and multistep dissociation mass spectrometry of which FTICR is uniquely capable. This range of capabilities for ESI-FTICR-MS should be widely useful in medicinal chemistry. 22 refs., 2 figs.

• Sponsoring Organization: USDOE
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 102729
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 34 Vol. 117; ISSN JACSAT; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
55 BIOLOGY AND MEDICINE
BASIC STUDIES
BINDING ENERGY
ENZYME INHIBITORS
ENZYMES
LIGANDS
MASS SPECTRA
MASS SPECTROSCOPY
PROTEINS
SULFONAMIDES