title: Glycation improves the thermostability of trypsin and chymotrypsin.
abstract: A novel glycation procedure, in vacuo glycation, was used to attach glucose covalently to the lysine residues of trypsin and chymotrypsin. Glycated trypsin and glycated chymotrypsin have greatly increased thermostability compared to the native enzymes. For example, glycated bovine trypsin, incubated at 50 degrees C and pH 8.0 for 3 h, retained more than 50% of its original activity whereas the native enzyme was inactivated under the same conditions. Similarly, after incubation at 50 degrees C and pH 8.0, glycated bovine chymotrypsin retained 45% of its original activity and the native enzyme was inactivated. Glycated porcine trypsin is exceptionally thermostable and could be used to digest native ribonuclease at 70 degrees C without the need for prior denaturation. The apparent increase in the thermal stability of the glycated proteins observed in activity measurements is also reflected by an increase in the T(m) values determined with differential scanning calorimetry (DSC) and circular dichroism (CD). The glycation does not alter the activity or specificity of these enzymes.
authors.affiliation: Department of Chemistry, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Van Thong
authors.initials: VT
authors.lastname: Pham
authors.forename: Erin
authors.initials: E
authors.lastname: Ewing
authors.forename: Harvey
authors.initials: H
authors.lastname: Kaplan
authors.forename: Christin
authors.initials: C
authors.lastname: Choma
authors.forename: Mary Alice
authors.initials: MA
authors.lastname: Hefford
mesh_terms: D002152:Calorimetry, Differential Scanning; D002918:Chymotrypsin / Q000737:chemistry* / Q000378:metabolism*; D002942:Circular Dichroism; D004795:Enzyme Stability; D006031:Glycosylation; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008239:Lysine / Q000378:metabolism; D013379:Substrate Specificity; D013997:Time Factors; D044366:Transition Temperature; D014357:Trypsin / Q000737:chemistry* / Q000378:metabolism*; D014618:Vacuum
chemical_list: D002918:Chymotrypsin; D014357:Trypsin; D008239:Lysine