Degradation of recombinant porcine growth hormone in the presence of guanidine hydrochloride

This study was conducted to investigate the effect of guanidine hydrochloride (Gdn HCl) on the rate of chemical degradation of recombinant porcine growth hormone (pGH) at alkaline pH. The protein was incubated in 0.2 M Tris buffer, pH 9 at 37°C containing Gdn HCl at concentrations ranging from 0 to...

Full description

Saved in:
Bibliographic Details
Published inInternational journal of pharmaceutics Vol. 173; no. 1; pp. 157 - 170
Main Authors McCrossin, Louise E, Charman, William N, Charman, Susan A
Format Journal Article
LanguageEnglish
Published Amsterdam Elsevier B.V 30.10.1998
Elsevier
Subjects
Biological and medical sciences
Chemical stability
General pharmacology
Medical sciences
Pharmaceutical technology. Pharmaceutical industry
Pharmacology. Drug treatments
Porcine growth hormone
Protein stability
Porcine growth hormone
Protein stability
Chemical stability
Degradation
STH
Peptide hormone
Kinetics
Recombinant protein
Conformation
Online AccessGet full text

Cover

More Information
Summary:This study was conducted to investigate the effect of guanidine hydrochloride (Gdn HCl) on the rate of chemical degradation of recombinant porcine growth hormone (pGH) at alkaline pH. The protein was incubated in 0.2 M Tris buffer, pH 9 at 37°C containing Gdn HCl at concentrations ranging from 0 to 6 M. The conformation of pGH under the different solution conditions was assessed by circular dichroism spectropolarimetry. Degradation was monitored by reversed phase HPLC (RP-HPLC), size exclusion chromatography (SEC) and SDS-PAGE. An associated form of pGH was populated in the presence of 3 and 4 M Gdn HCl, whereas the protein was completely unfolded in 5 and 6 M Gdn HCl. The apparent degradation rate constant determined by RP-HPLC increased by a factor of 18 in the presence of 3 M Gdn HCl and by a factor of five in the presence of 6 M Gdn HCl relative to that in buffer alone. RP-HPLC and SEC data suggested that the product distribution also differed between buffer and solutions containing Gdn HCl. While the increased rate of degradation for the denatured state was not unexpected, the dramatic increase at an intermediate Gdn HCl concentration was surprising and indicated the importance of considering chemical instability when proteins are exposed to denaturants.
ISSN:0378-5173
1873-3476
DOI:10.1016/S0378-5173(98)00235-X