Premium
β‐Lactamase ragged ends detected by electrospray mass spectrometry correlates poorly with multiple banding on isoelectric focusing
Author(s) -
Payne David J.,
Skett Peter W.,
Aplin Robin T.,
Robinson Carol V.,
Knowles David J. C.
Publication year - 1994
Publication title -
biological mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1052-9306
DOI - 10.1002/bms.1200230307
Subject(s) - bacillus cereus , isoelectric focusing , chemistry , mass spectrometry , isoelectric point , chromatography , electrospray , cereus , enzyme , biochemistry , biology , bacteria , genetics
Purified preparations of TEM‐2, P99, Bacillus cereus I and B. cereus II β‐lactamases were examined by electro‐spray (ES) mass spectrometry. The ES mass spectra of the B. cereus enzymes revealed the presence of four to five components of different mass, corresponding to the loss of different numbers of N‐terminal amino acids (ragged ends). The ES mass spectra of both TEM‐2 and P99 consisted of a single component with no evidence of ragged ends. All four β‐lactamase preparations were visualized on isoelectric focusing (IEF) gels stained with nitrocefin to investigate a possible correlation between IEF patterns and ragged ends. Multiple banding patterns were seen with each β‐lactamase preparation. Although these may correlate with the presence of ragged ends in the two B. cereus preparations, the satellite bands seen with P99 and TEM‐2 were not associated with differences detected by ES mass spectrometry. In this study we have shown for the first time that β‐lactamase satellite bands seen on IEF are not always associated with ragged ends. Furthermore, we have illustrated the use of ES mass spectrometry to characterize the extent of ragged end formation in protein samples. This is of particular significance if the sample is required for detailed biochemical or crystallography experiments.