Effect of glycosylation on the stability of alpha1-antitrypsin toward urea denaturation and thermal deactivation

Cited 54 time in scopus
Metadata Downloads
Effect of glycosylation on the stability of alpha1-antitrypsin toward urea denaturation and thermal deactivation
Ki Sun Kwon; Myeong Hee Yu
Bibliographic Citation
Biochimica et Biophysica Acta-General Subjects, vol. 1335, no. 3, pp. 265-272
Publication Year
The effects of glycosylation on the stability of human α1-antitrypsin were investigated. The transition midpoints in urea-induced equilibrium unfolding of a non-glycosylated recombinant, a yeast version of glycosylated, and human plasma α1-antitrypsin were 1.8 M, 2.2 M, and 2.5 M at 25°C, respectively. Kinetic analyses of unfolding and refolding revealed that glycosylation retarded the unfolding without affecting the refolding rate significantly, suggesting that the stability increase is due to the stabilization of the native state as opposed to the destabilization of the unfolded state. In thermal deactivation, which is a heat-induced aggregation process, the ungycosylated recombinant α1-antitrypsin was deactivated most easily, which was followed in order by the yeast, and the plasma form. The results indicate that glycosylation confers the increase in stability of α1-antitrypsin, and that the oligomannose sugars present on the yeast form produce a less stable molecule than the complex type sugars on the plasma form. It appears that the effect of glycosylation on the enhancement of thermal resistance is exerted through the increase in conformational stability. However, a stable recombinant variant (Phe 51 → Cys) that showed the same conformational stability as the plasma form was less resistant to thermal denaturation than the plasma α1-antitrypsin. The results suggest that the existence of carbohydrate moiety per se as well as the conformational stability contribute to the kinetic stability of α1-antitrypsin toward aggregation.
Glycosylationα1-AntitrypsinConformational stabilityKinetic stabilityAggregation
Appears in Collections:
Aging Convergence Research Center > 1. Journal Articles
Files in This Item:
  • There are no files associated with this item.

Items in OpenAccess@KRIBB are protected by copyright, with all rights reserved, unless otherwise indicated.