Global differential non-gel proteomics by quantitative and stable labeling of tryptic peptides with oxygen-18.
We describe a protocol for quantitative labeling of tryptic peptides with oxygen-18. Proteins are first digested in natural water with trypsin, the pH is then lowered to 4.5 and the mixture is dried. Oxygen-18 water is added and two oxygen-18 atoms are incorporated at the peptides' carboxyl termini. Trypsin is finally inactivated by cysteine alkylation under denaturing conditions, which blocks oxygen back-exchange. The general value of this labeling strategy for differential proteomics is illustrated by the analysis and identification of several couples of differently labeled amino terminal peptides isolated from a human platelet proteome by a previously described chromatographic procedure.
Staes
An
A
Department of Medical Protein Research, Faculty of Medicine and Health Sciences, Ghent University, A Baertsoenkaai 3, B-9000 Ghent, Belgium.
Demol
Hans
H
Van Damme
Jozef
J
Martens
Lennart
L
Vandekerckhove
Joël
J
Gevaert
Kris
K
D000595:Amino Acid Sequence; D001792:Blood Platelets / Q000737:chemistry; D006801:Humans; D007553:Isotope Labeling; D008969:Molecular Sequence Data; D010103:Oxygen Isotopes / Q000737:chemistry; D010446:Peptide Fragments / Q000737:chemistry*; D010449:Peptide Mapping; D011506:Proteins / Q000737:chemistry; D020543:Proteome / Q000737:chemistry; D040901:Proteomics / Q000379:methods*; D014357:Trypsin / Q000737:chemistry*
D010103:Oxygen Isotopes; D010446:Peptide Fragments; D011506:Proteins; D020543:Proteome; D014357:Trypsin