Keywords: Mass spectrometry, protein interactions, acetylation, labeling
In our modified approach, acetylation labeling mass spectrometry (ALMS), a slightly higher anhydride-to-protein ratio is used than previously reported.
Each acetylation will result in a mass increase of 42 Da.
Threonine and glycine had an increase in mass of 42 Da corresponding to the acetylation of only the amine-terminus.
With the expectation that two cysteines may be bound to the heme group, the observed 40 labels is several more than the expected 36, but similar enough to strongly suggest that the eight amino acids that were observed to undergo acetylation as monomers also undergo acetylation reactions within a polypeptide, in addition to verifying the acetylation of an array of amino acids, the test demonstrates the capability of ALMS to observe two different protein conformations.