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摘要
Isothermal titration calorimetry was used to determine the enzymatic activity and thermodynamic activation parameters of Arthrobacter ureafaciens sialidase with the sialyl substrates -2,3-, -2,6-sialyllactoses and -2,8-sialic acid dimer. By monitoring the heat released during hydrolysis, the Michaelis constant (K-m), catalytic rate constant (k(cat)), activation energy, activation Gibbs energy, enthalpy, and entropy for different monovalent sialyl conjugates were calculated and found to be consistent with those derived by chromatographic or colorimetric assays. The observed decreases in the activation energy and transition entropy of sialyllactoses were larger than the Michaelis activation parameters of lactose-free di-sialic acid because of the specific enzyme activity of A. ureafaciens sialidase.
- 出版日期2018-2
