Optimization of sample preparation for peptide sequencing by MALDI-TOF photofragment mass spectrometry.
This paper describes the optimization of sample preparation for MALDI 193-nm photofragment ion time-of-flight mass spectrometry to sequence small to medium-sized peptides from peptide mixtures. We show that matrix additives, such as fructose and phenylbutyric acid have a dramatic effect on the abundance of fragment ions observed in the post-source decay spectra. A dried-droplet MALDI matrix consisting of 1:1 alpha-cyano-4-hydroxycinnamic acid/fructose proves to be an excellent matrix for photodissociation because [M + H]+ ions are formed with low internal energies, and the photofragment ion spectrum contains high abundances of sequence-informative ions. The addition of fructose appears to improve overall sample homogeneity and durability, as compared to conventional alpha-cyano-4-hydroxycinnamic acid dried-droplet preparations. MALDI-TOF photodissociation is then used to selectively sequence the peptides bradykinin (RPPGFSPFR), des-Arg9 bradykinin (RPPGFSPF), and substance P-amide (RPKPQQFFGLM-NH2) from a mixture of five peptides.
Hettick
J M
JM
Department of Chemistry, Texas A&M University, College Station 77842-3012, USA.
McCurdy
D L
DL
Barbacci
D C
DC
Russell
D H
DH
D000818:Animals; D003373:Coumaric Acids; D005632:Fructose; D006801:Humans; D009842:Oligopeptides / Q000737:chemistry; D020539:Sequence Analysis, Protein; D013048:Specimen Handling; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation / Q000379:methods* / Q000592:standards
D003373:Coumaric Acids; D009842:Oligopeptides; C007175:alpha-cyano-4-hydroxycinnamate; D005632:Fructose