title: Comparison of predicted extinction coefficients of monoclonal antibodies with experimental values as measured by the Edelhoch method.
abstract: Pace et al. (1995) [1] recommended an equation used to predict extinction coefficient of a protein. However, no antibody data was included in the development of this equation. The main objective of this study was to therefore investigate how the predicted value of the extinction coefficient is comparable to the experimentally determined extinction coefficient of antibodies measured by the Edelhoch method. We have measured the extinction coefficients (ɛ) of 13 IgG1 monoclonal antibodies (mAbs) in phosphate buffer at pH 7.2. The maximum variability in the experimentally measured extinction coefficient of a given mAb molecule was found to be about 2%. Experimentally determined extinction coefficients of all mAbs were found to be lower than the predicted value, with the maximum difference found to being 4.7%. The highest and lowest values of experimental extinction coefficient among the thirteen IgG1 monoclonal antibodies obtained were 230525.9M(-1)cm(-1) (i.e. 1.55(mg/ml)(-1)cm(-1)) and 191,411.6M(-1)cm(-1) (i.e. 1.29(mg/ml)(-1)cm(-1)). A difference of <3% (with respect to mean value) was observed between the experimental and predicted values of the extinction coefficient. A comprehensive analysis and interpretation of the comparison of the predicted and experimentally determined extinction coefficient by the Edelhoch method is discussed in terms of structural characterization and accessible surface area (ASA).
authors.affiliation: Formulation Development, CMC Development, Eli Lilly and Company, 59-61 ImClone Drive, Branchburg, NJ 08876, USA. Electronic address: haripada.maity@lilly.com.
authors.forename: Haripada
authors.initials: H
authors.lastname: Maity
authors.affiliation: Formulation Development, CMC Development, Eli Lilly and Company, 59-61 ImClone Drive, Branchburg, NJ 08876, USA.
authors.forename: Alex
authors.initials: A
authors.lastname: Wei
authors.affiliation: Formulation Development, CMC Development, Eli Lilly and Company, 59-61 ImClone Drive, Branchburg, NJ 08876, USA.
authors.forename: Ethan
authors.initials: E
authors.lastname: Chen
authors.affiliation: Antibody Technology Department, Alexandria Center for Life Sciences, Eli Lilly and Company, 450 East 29th Street, NY 10016, USA; Structural Biology Department, Alexandria Center for Life Sciences, Eli Lilly and Company, 450 East 29th Street, NY 10016, USA.
authors.forename: Jaafar N
authors.initials: JN
authors.lastname: Haidar
authors.affiliation: Formulation Development, CMC Development, Eli Lilly and Company, 59-61 ImClone Drive, Branchburg, NJ 08876, USA.
authors.forename: Arvind
authors.initials: A
authors.lastname: Srivastava
authors.affiliation: Formulation Development, CMC Development, Eli Lilly and Company, 59-61 ImClone Drive, Branchburg, NJ 08876, USA.
authors.forename: Joel
authors.initials: J
authors.lastname: Goldstein
mesh_terms: D065966:Absorption, Physicochemical; D061067:Antibodies, Monoclonal, Humanized / Q000737:chemistry*; D007074:Immunoglobulin G / Q000737:chemistry; D007135:Immunoglobulin Variable Region / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D014364:Tryptophan / Q000737:chemistry; D014443:Tyrosine / Q000737:chemistry
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D007074:Immunoglobulin G; D007135:Immunoglobulin Variable Region; D014443:Tyrosine; D014364:Tryptophan
keywords: Accessible surface area (ASA); Edelhoch method; Molar extinction coefficient