engleski

Evaluation of Recombinant Human Interferon a-2b Structure and Stability by In-gel Tryptic Digestion, H/D Exchange and Mass Spectrometry

Stability and structure of recombinant interferon a-2b (rHuINF a-2b) was studied by mass spectrometry (MALDI-TOF and Q-TOF MS), chromatography (LC-UV-FLD-DAD, LC-MS) and CD spectroscopy. Besides analysis of the substance according to Ph. Eur. methods, two additional mass spectrometric methods were developed. The aim of both methods was to estimate structure-stability relationship connected to methionine oxidation or protein degradation. Preservation or degradation of protein structure was confirmed by H/D exchange in four separate experiments. The kinetics of deuterium incorporation into macromolecule was monitored over 2670 minutes. Isoforms of rHuINF a-2b were separated by 2-D gel electrophoresis. In-gel digestion with trypsin and mass spectrometric analysis, performed on four separated isoforms at the mass corresponding to the mass of rHuINF a-2b with oxidized methionines, confirmed oxidation of all methionines to a different extent. Another four isoforms observed in 2-D gel are most likely dimers of the same macromolecules with scrambled disulphide bridges. Oxidation and dimerisation are consequences of protein interaction with oxidizing reagents in polyacrilamide gel.

recombinant human interferon a-2b; stability; MALDI-TOF MS; H/D exchange; 2-D gel electrophoresis; methionine oxidation

S.I: Hyphenated Techniques in Pharmaceutical and Biomedical Analysis ; B. Chankvetadze (ur.).