The catalase family of enzymes,which include a variety with a binuclear manganese active site,mitigate the risk from reactive oxygen species by facilitating the disproportionation of hydrogen peroxide into molecular o...The catalase family of enzymes,which include a variety with a binuclear manganese active site,mitigate the risk from reactive oxygen species by facilitating the disproportionation of hydrogen peroxide into molecular oxygen and water.In this work,hydrogen peroxide disproportionation using complexes formed between manganese and cyclen or pyclen were investigated due to the spectroscopic similarities with the native MnCAT enzyme.Potentiometric titrations were used to construct speciation diagrams that identify the manganese complex compositions at different pH values.Each complex behaves as a functional mimic of catalase enzymes.UV-visible spectroscopic investigations of the H_(2)O_(2)decomposition reaction yielded information about the structure of the initial catalyst and intermediates that include monomeric and dimeric species.The results indicate that rigidity imparted by the pyridine ring of pyclen is a key factor in increased TON and TOF values measured compared to cyclen.展开更多
基金financial support from the National Institute of Health(NIGMS,R15GM123463 to K.N.G.and GM117511-02 to B.S.P.)the National Science Foundation(CHE,1709369 to B.S.P.)+2 种基金financial support from TCU Andrews Institute of Mathematics&Science Education(to K.G.)Cambridge Isotope Laboratories,and TCU Research and Creativity Activity Grant(to K.G.)start-up funding from Texas Christian University for support of this work.
文摘The catalase family of enzymes,which include a variety with a binuclear manganese active site,mitigate the risk from reactive oxygen species by facilitating the disproportionation of hydrogen peroxide into molecular oxygen and water.In this work,hydrogen peroxide disproportionation using complexes formed between manganese and cyclen or pyclen were investigated due to the spectroscopic similarities with the native MnCAT enzyme.Potentiometric titrations were used to construct speciation diagrams that identify the manganese complex compositions at different pH values.Each complex behaves as a functional mimic of catalase enzymes.UV-visible spectroscopic investigations of the H_(2)O_(2)decomposition reaction yielded information about the structure of the initial catalyst and intermediates that include monomeric and dimeric species.The results indicate that rigidity imparted by the pyridine ring of pyclen is a key factor in increased TON and TOF values measured compared to cyclen.
