EMAIL THIS PAGE TO A FRIEND

Pharmeuropa scientific notes

Rapid identification of somatropin by peptide-mass fingerprinting, using MALDI-TOF mass spectrometry.


PMID 19275868

Abstract

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 %.