Biosimilars/Research
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Posted 17/06/2016
Although produced under strict quality control(s) nascent endogenous proteins and glycoproteins (P/GP) are structurally heterogeneous and subject to further structural changes throughout their in vivo life cycle. A nascent polypeptide chain may be subject to co-translational modifications (CTMs) as it is extruded from the ribosome tunnel, e.g. the addition of oligosaccharide; edited for correct folding and initial oligosaccharide processing within the endoplasmic reticulum and subject to post-translational modifications (PTMs) during passage through the Golgi apparatus. The functional activity of a P/GP may be dependent on further chemical modifications (CMs), e.g. deamidation, enzymatic cleavage. These heterogeneities are compounded when determining the structure of a purified P/GP because further CMs may be introduced during its isolation, purification and characterization [1].