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J Clin Exp Tox 2017 | Volume 1 | Issue 2
Toxicology and Pharmacology
November 01-02, 2017 | Toronto, Canada
International Conference on
Characterization of methionine oxidized human recombinant erythropoietin by nano LC-ESI-MSMS;
Isoform distribution and biological activity
M Reza Khorramizadeh
1
, Mohammad Hossein Hedayati
1
, Dariush Norouzian
2
, Mahdi Aminian
1
, Shahram Teimourian
3
and
Reza Ahangari Cohan
2
1
Tehran University of Medical Sciences, Iran
2
Pasteur Institute of Iran, Iran
3
Iran University of Medical Sciences, Iran
M
ethionine (Met) oxidation is a significant form
of protein damage caused by endogenous or
environmental oxidizing agents. In this study we examined
the effect of increasing levels of Methionine-54 oxidation
on the isoform distribution and biological activity of the
human recombinant erythropoietin. Mass spectrometry
was applied to determine and compare the Met oxidation
level of three batches of human recombinant erythropoietin.
Isofrom distribution of the analyzed products was assessed
by capillary zone electrophoresis (CZE) method. The
calculated area percent of isoforms 2-4 which belongs to
more acidic glycoforms, were decreased with increasing
the level of methionine oxidation in all samples. Also, the
results showed that the percent of isoforms 5-8 (more basic)
were increased in all samples along with the elevating Met
oxidation level. The
in vivo
biological activity of proteins was
decreased by increasing the level of oxidation. In conclusion,
Met oxidation level in human recombinant erythropoietin
showed significant association with the net charge and
isoform distribution of the glycoprotein and could be applied
for monitoring and validation of production processes and
quality control assessments.
Speaker Biography
M Reza Khorramizadeh, is a full Professor at Tehran University of Medical Sciences
(TUMS), directs Biosensor Research Center and newly instituted Zebra Fish Core Lab at
Endocrinology and Metabolic Molecular-Cellular Sciences Institute. Concurrently, he is
a 2nd affiliation to the Dept. of Medical Biotechnology, School of Advanced Technology
in Medicine, TUMS.
e:
khoramza@tums.ac.ir