title: Applications of circular dichroism (CD) for structural analysis of proteins: qualification of near- and far-UV CD for protein higher order structural analysis.
abstract: Circular dichroism (CD) spectroscopy is routinely used in the biopharmaceutical industry to study the effects of manufacturing, formulation, and storage conditions on protein conformation and stability, and these results are often included in regulatory filings. In this context, the purpose of CD spectroscopy is often to verify that a change in the formulation or manufacturing process of a product has not produced a change in the conformation of a protein. A comparison of two or more spectra is often required to confirm that the protein's structure has been maintained. Traditionally, such comparisons have been qualitative in nature, based on visually inspecting the overlaid spectra. However, visual assessment is inherently subjective and therefore prone to error. Furthermore, recent requests from regulatory agencies to demonstrate the suitability of the CD spectroscopic method for the purpose of comparing spectra have highlighted the need to appropriately qualify CD spectroscopy for characterization of biopharmaceutical protein products. In this study, we use a numerical spectral comparison approach to establish the precision of the CD spectroscopic method and to demonstrate that it is suitable for protein structural characterization in numerous biopharmaceutical applications.
authors: Formulation and Analytical Resources Department, Amgen Inc., Thousand Oaks, California 91320, USA. cynthial@amgen.com
authors: Cynthia H
authors: CH
authors: Li
authors: Xichdao
authors: X
authors: Nguyen
authors: Linda
authors: L
authors: Narhi
authors: Letha
authors: L
authors: Chemmalil
authors: Edward
authors: E
authors: Towers
authors: Salman
authors: S
authors: Muzammil
authors: John
authors: J
authors: Gabrielson
authors: Yijia
authors: Y
authors: Jiang
mesh_terms: D000465:Algorithms; D002138:Calibration; D002942:Circular Dichroism; D006863:Hydrogen-Ion Concentration; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet
chemical_list: D011506:Proteins