Chemical cleavage at aspartyl residues for protein identification.
An alternative method to enzymatic digestion for protein identification by mass spectrometry has been developed that is based on chemical cleavage by formic acid. This method was tested on gel-purified apomyoglobin and BSA, as well as unknown proteins that cofractionate with Tyl-virus-like particles from Saccharomyces cerevisiae. Cleavage at aspartyl residues was found to be efficient and specific, and this specificity of cleavage lent itself easily to database searches. Parallel digestions using trypsin were also performed. The formic acid cleavage method generated comparable or better results than tryptic digestion for protein identification.
Li
A
A
Protein Chemistry Laboratory, AIDS Vaccine Program, SAIC Frederick, NCI at Frederick, Maryland 21702-1201, USA. liai@ncifcrf.gov
Sowder
R C
RC
Henderson
L E
LE
Moore
S P
SP
Garfinkel
D J
DJ
Fisher
R J
RJ
D000818:Animals; D001224:Aspartic Acid / Q000737:chemistry*; D005561:Formates / Q000737:chemistry; D006868:Hydrolysis; D010446:Peptide Fragments / Q000737:chemistry; D010449:Peptide Mapping / Q000379:methods*; D011506:Proteins / Q000737:chemistry*; D020539:Sequence Analysis, Protein; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D005561:Formates; D010446:Peptide Fragments; D011506:Proteins; C030544:formic acid; D001224:Aspartic Acid