Improved matrix-assisted laser desorption/ionization mass spectrometric analysis of tryptic hydrolysates of proteins following guanidination of lysine-containing peptides.
Analysis of tryptic digests of proteins using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry commonly results in superior detection of arginine-containing peptides compared with lysine-containing counterparts. The effect is attributable in part to the greater stability of the arginine-containing peptide ions associated with the sequestration of the single ionizing proton on the arginine side-chain. Reaction of peptides with O-methylisourea resulted in conversion of lysine to homoarginine residues with consequent improved detection during MALDI-MS. Analysis of the underivatized tryptic digest of the yeast protein, enolase, revealed peptides representing 20% of the protein; the corresponding figure after derivatization was 46%.
Brancia
F L
FL
Department of Biomolecular Sciences and UMIST, Manchester, UK.
Oliver
S G
SG
Gaskell
S J
SJ
D000426:Alcohol Dehydrogenase / Q000378:metabolism; D000595:Amino Acid Sequence; D005656:Fungal Proteins / Q000378:metabolism; D006146:Guanidines / Q000032:analysis / Q000378:metabolism*; D006709:Homoarginine / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism*; D008782:Methylurea Compounds / Q000378:metabolism; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism*; D010751:Phosphopyruvate Hydratase / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D014357:Trypsin / Q000378:metabolism; D015003:Yeasts
D005656:Fungal Proteins; D006146:Guanidines; D008782:Methylurea Compounds; D010446:Peptide Fragments; D006709:Homoarginine; C002249:O-methylisourea; D000426:Alcohol Dehydrogenase; D014357:Trypsin; D010751:Phosphopyruvate Hydratase; D008239:Lysine