title: Mechanisms of thermoinactivation of endoglucanase I from Trichoderma reesei QM 9414.
abstract: The mechanism of irreversible thermoinactivation of endoglucanase I from Trichoderma reesei has been determined at 70 degrees C at the pH of maximum enzyme activity. The time-course of thermoinactivation did not follow first-order kinetics and kinetic constants of the process were dependent on enzyme concentration, suggesting that aggregation was the main process leading to irreversible inactivation. The enzyme was extremely resistant to urea, which in fact seemed to stabilize it against temperature. Disulphide exchange, deamidation and hydrolysis of peptide bonds were also responsible for the loss of enzyme activity at 70 degrees C.
authors.affiliation: Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias Químicas, Universidad Complutense, Madrid, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Dominguez
authors.forename: C
authors.initials: C
authors.lastname: Acebal
authors.forename: J
authors.initials: J
authors.lastname: Jimenez
authors.forename: I
authors.initials: I
authors.lastname: de la Mata
authors.forename: R
authors.initials: R
authors.lastname: Macarron
authors.forename: M P
authors.initials: MP
authors.lastname: Castillon
mesh_terms: D000645:Ammonium Sulfate / Q000494:pharmacology; D043366:Cellulose 1,4-beta-Cellobiosidase; D002942:Circular Dichroism; D003300:Copper / Q000494:pharmacology; D004220:Disulfides / Q000378:metabolism; D004789:Enzyme Activation; D006026:Glycoside Hydrolases / Q000378:metabolism*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011487:Protein Conformation; D013056:Spectrophotometry, Ultraviolet; D014242:Trichoderma / Q000201:enzymology*; D014508:Urea / Q000494:pharmacology
chemical_list: D004220:Disulfides; D003300:Copper; D014508:Urea; C028419:cuprous chloride; D006026:Glycoside Hydrolases; D043366:Cellulose 1,4-beta-Cellobiosidase; D000645:Ammonium Sulfate