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An investigation of the binding of protein proteinase inhibitors to trypsin by electrospray ionization mass spectrometry
Author(s) -
Kraunsoe James A.E.,
Aplin Robin T.,
Green Brian,
Lowe Gordon
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)01081-2
Subject(s) - chemistry , electrospray ionization , trypsin , dissociation (chemistry) , electrospray , mass spectrometry , ionization , crystallography , ion , chromatography , enzyme , biochemistry , organic chemistry
The binding of BPTI and SBTI with trypsin has been investigated by ESI MS, using the mutant K15V‐BPTI and the chemically modified RcamBPTI as controls. Although high cone voltages (+80 V) produce sharp spectra of BPTI, RcamBPTI, SBTI and trypsin alone, the complexes of BPTI, RcamBPTI and SBTI with trypsin undergo partial dissociation due to collisional activation. At lower cone voltages (+40 V) these non‐covalent complexes are stable. The charge distribution on the trypsin and the inhibitors produced by gas phase dissociation of the complexes are markedly different from those of the components alone, indicating that ESI MS provides a novel probe for exploring the ionic interactions at the contact surface of proteins. Moreover, by determining the cone voltage at which the gas phase dissociation of complexes occurs it may be possible to use ESI MS to compare the binding energies of closely related complexes.