Rapid identification of somatropin by peptide-mass fingerprinting, using MALDI-TOF mass spectrometry.
This paper presents a rapid method based on MALDI-TOF-MS peptide mass finger printing (PMF) for identification of somatropin. The protein was digested with either trypsin or endoproteinase Lys-C prior to MALDI-MS analysis. The identification was then performed by comparing the measured mass spectra with those predicted in-silico. The cysteine residues at positions 182, 190 and 165 in the protein were identified by carboxyamidomethylation of the cysteine residues with iodoacetamide. One of the two disulfide bridges connecting C182 and C189 was observed in the peptide mass mapping of the unmodified tryptic digest. Sequence coverage obtained from individual trypsin and Lys-C was 79 % and 60 %, respectively. Sequence coverage of both maps together was 98 %.
Amini
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Medical Products Agency (MPA), Box 26, Dag Hammarskjölds väg 42, 751 03 Uppsala, Sweden. Ahmad.Amini@mpa.se
D000595:Amino Acid Sequence; D003198:Computer Simulation; D019382:Human Growth Hormone / Q000032:analysis*; D006801:Humans; D007202:Indicators and Reagents; D008666:Metalloendopeptidases / Q000737:chemistry; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis; D010449:Peptide Mapping / Q000379:methods*; D011994:Recombinant Proteins / Q000032:analysis; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014357:Trypsin / Q000737:chemistry
D007202:Indicators and Reagents; D010446:Peptide Fragments; D011994:Recombinant Proteins; D019382:Human Growth Hormone; D014357:Trypsin; D008666:Metalloendopeptidases; C039830:peptidyl-Lys metalloendopeptidase