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Effect of shear on the inactivation kinetics of the enzyme dextransucrase
Author(s) -
Lencki Robert W.,
Tecante Alberto,
Choplin Lionel
Publication year - 1993
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260420907
Subject(s) - dextransucrase , kinetics , chemistry , enzyme kinetics , enzyme , biochemistry , biology , physics , lactic acid , genetics , quantum mechanics , bacteria , leuconostoc mesenteroides , active site
An inactivation model previously developed to characterize the rate of enzyme activity loss in unstirred solutions was extended to take into account orthokinetic interactions resulting from convective mixing. A synergistic relationship between shear rate and temperature was observed; the rate of inactivation of the enzyme dextransucrase was unaffected by the action of shear below 25°C, but was increased by the shear rate at 30°C. Shear rate does not appear to influence the equilibrium between native and denatured dextransucrase either directly in solution or indirectly by augmenting the turnover of the gas–liquid interface. However, a second‐order plot of the inverse of relative activity ( A O / A ) versus Gt (shear rate × time) of dextransucrase at a constant temperature was linear because of the influence of shear on the coagulation of the denatured enzyme. The addition of 0.01 g L −1 of polyethylene glycol (MW 20,000) blocked this coagulation reaction, thereby completely inhibiting the shear‐induced inactivation of dextransucrase at 30°C. © 1993 John Wiley & Sons, Inc.