Comparative properties of human α‐1‐proteinase inhibitor glycosylation variants

Abstract

Variant forms of human α‐1‐proteinase inhibitor (α‐1‐PI), obtained by the treatment of human Hep G2 cells with specific inhibitors of glycosylation were tested for both inhibitory activity and heat stability. All were found to have the same second‐order association rate with human neutrophil elastase, indicating a lack of importance of the carbohydrate moiety. In contrast, incompletely glycosylated forms of α‐1‐PI were found to be heat sensitive relative to the mature protein, suggesting a role for carbohydrate in protein stabilization.