On the analysis of bovine trypsin by electrospray-mass spectrometry

Abstract In this paper the results obtained from an electrospray mass spectrometric (ES-MS) analytical study of commercial grade bovine trypsin are presented and discussed. It is proven, somewhat contrary to an earlier report, that ES-MS analysis may be performed routinely on a triple quadrupole mass spectrometer using the normal ES-MS raw data transformation procedures to identify and quantify the three forms of trypsin, namely, β, α and ψ, present in the samples. Further, it was found that all of the samples analysed contained small amounts of two peptides of Mr = 5447 and 17,882 Da, which are postulated to originate from catalytic cleavage of α-trypsin by β-trypsin.