Site-selective chemical protein glycosylation protects from autolysis and proteolytic degradation

Glycosylation is often cited as having a stabilizing effect upon proteins with respect to proteolysis, thermolysis and other forms of degradation. We present here a model study on an autolytic protease that has been chemically glycosylated to produce single glycoforms. The resulting glycosylated enzymes are more stable with respect to their own autolytic degradation and that by other proteases. Kinetic parameters for protease activity with respect to the degradation of small-molecule amide substrate reveal no significant change in inherent activity thereby suggesting that reduced autolysis and proteolysis are a consequence of stabilization, perhaps by steric blockade of cleavage points or alteration of local unfolding kinetics. Variation in glycan identity suggests that greater glycan size leads to greater stabilization.