(15)(V/K) kinetic isotope effect and steady-state kinetic analysis for the transglutaminase 2 catalyzed deamidation and transamidation reactions

作者：Wells Evan A; Anderson Mark A; Zeczycki Tonya N^*

来源：Archives of Biochemistry and Biophysics, 2018, 643: 57-61.

DOI：10.1016/j.abb.2018.02.013

• Isotope effects
• Polyamidation
• Deamidation
• Transglutaminase
• Steady-state kinetics

The Ca2+-dependent deamidation and transamidation activities of transglutaminase 2 (TG2) are important to numerous physiological and pathological processes. Herein, we have examined the steady-state kinetics and (15)(V/K) kinetic isotope effects (KIEs) for the TG2-catalyzed deamidation and transamidation of N-Benzyloxycarbonyl-l-Glutaminylglyeine (Z-Gln-Gly) using putrescine as the acyl acceptor substrate. Kinetic parameters determined from initial velocity plots are consistent with previously proposed mechanisms. Significant differences in the (15)(V/K) KIEs on NH3 release determined for the deamidation (0.2%) and the transamidation (2.3%) of Z-Gln-Gly suggest the rate-limiting steps of TG2 active site acylation are dependent on the presence of the acyl acceptor. We propose a plausible mechanistic explanation where substrate-induced conformational changes may play a role in promoting catalysis.

• 出版日期2018-4-2
• 单位East Carolina