Controlling deamidation rates in a model peptide: Effects of temperature, peptide concentration, and additives

The rate of deamidation of the Asn residue in Val‐Tyr‐Pro‐Asn‐Gly‐Ala (VYPNGA), a model peptide, was determined at pH 9 (400 mM Tris buffer) as a function of temperature and peptide concentration. Over the temperature range 5–65°C, deamidation followed Arrhenius behavior, with an apparent activation...

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Bibliographic Details
Published in:Journal of pharmaceutical sciences 2001-12, Vol.90 (12), p.2141-2148
Main Authors: Stratton, Lewis P., Kelly, R.Michael, Rowe, Jared, Shively, Jesse E., Smith, D.David, Carpenter, John F., Manning, Mark C.
Format: Article
Language:English
Subjects:
Amides
Arrhenius plot
Asparagine - chemistry
Biological and medical sciences
Chromatography, High Pressure Liquid
Circular Dichroism
deamidation
Excipients - chemistry
gel
General pharmacology
Medical sciences
Models, Chemical
peptide stability
Peptides - chemistry
Pharmacology. Drug treatments
Physicochemical properties. Structure-activity relationships
poloxamer
Poloxamer - chemistry
Protein Conformation
Sucrose - chemistry
Temperature
Thermodynamics
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Summary:The rate of deamidation of the Asn residue in Val‐Tyr‐Pro‐Asn‐Gly‐Ala (VYPNGA), a model peptide, was determined at pH 9 (400 mM Tris buffer) as a function of temperature and peptide concentration. Over the temperature range 5–65°C, deamidation followed Arrhenius behavior, with an apparent activation energy of 13.3 kcal/mol. Furthermore, increasing the peptide concentration slows the rate of deamidation. Self‐stabilization with respect to deamidation has not been reported previously. The rate of deamidation was also determined in the presence of sucrose and poloxamer 407 (Pluronic F127). In both cases, the rate of deamidation was retarded by up to 40% at 35°C. In aqueous solutions containing poloxamer 407, the degree of stabilization is independent of formation of a reversible thermosetting gel. With sucrose, maximum reduction in the deamidation rate was attained with as little as 5% (w/v). Addition of sucrose results in a greater conformational preference for a type II β‐turn structure, which presumably is less prone to intramolecular cyclization and subsequent deamidation. © 2001 Wiley‐Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 90:2141–2148, 2001
ISSN:0022-3549
1520-6017
DOI:10.1002/jps.1165