Aqueous stability of human epidermal growth factor 1-48.
Human epidermal growth factor 1-48 (hEGF 1-48, Des(49-53)hEGF) is a single chain polypeptide (48 amino acids; 3 disulfide bonds; 5445 Da) possessing a broad spectrum of biologic activity including the stimulation of cell proliferation and tissue growth. In this study, three primary aqueous degradation products of hEGF 1-48 were isolated using isocratic, reverse phase/ion-pair HPLC. The degradation products were characterized using amino acid sequencing, electrospray ionization mass spectrometry, isoelectric focusing, and degradation kinetics. Results indicate that hEGF 1-48 degrades via oxidation (Met21), deamidation (Asn1), and succinimide formation (Asp11). The relative contribution of each degradation pathway to the overall stability of hEGF 1-48 changes as a function of solution pH and storage condition. Succinimide formation at Asp11 is favored at pH < 6 in which aspartic acid is present mostly in its protonated form. Deamidation of Asn1 is favored at pH > 6. The relative contribution of Met21 oxidation is increased with decreasing temperature, storage as a frozen solution (-20 degrees C), and exposure to fluorescent light.
Senderoff
R I
RI
Department of Pharmaceutics, Parke-Davis Pharmaceutical Research Division, Warner-Lambert Company, Morris Plains, New Jersey 07950.
Wootton
S C
SC
Boctor
A M
AM
Chen
T M
TM
Giordani
A B
AB
Julian
T N
TN
Radebaugh
G W
GW
D000595:Amino Acid Sequence; D004355:Drug Stability; D004815:Epidermal Growth Factor / Q000737:chemistry*; D005453:Fluorescence; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D013696:Temperature
D004815:Epidermal Growth Factor