Journal of Porphyrins and Phthalocyanines p. 824 - 831 (2017)
Update date:2022-08-11
Topics:
Mashima, Tsuyoshi
Oohora, Koji
Hayashi, Takashi
To convert an originally tyrosine-coordinated heme to histidine-coordinated heme in hexameric tyrosine-coordinated hemoprotein, HTHP, Tyr45, a residue coordinating to the heme cofactor, and Arg25 located in the distal site are replaced with Phe45 and His25, respectively in each of the subunits of the protein. The obtained HTHP mutant (HTHPR25H/Y45F) was characterized by SDS-PAGE, ESI-TOF MS, dynamic light scattering measurements and size exclusion chromatography. These analyses indicate that HTHPR25H/Y45F maintains its stable hexameric structure with the altered ligation of each of the heme cofactors. Comparison of UV-vis absorption spectra of the ferric-, ferrous-, CO-and CN-forms of HTHPR25H/Y45F with those of several well-known His-ligated hemoproteins indicates that heme is coordinated by the His25 residue. The reaction of HTHPR25H/Y45F with cumene hydroperoxide produces both cumyl alcohol and acetophenone in a 2.3:1 ratio, indicating that heterolytic O-O bond cleavage dominantly occurs to form the two-electron oxidized species known as compound I. Peroxidase activity of HTHPR25H/Y45F is found to follow Michaelis-Menten kinetics. The kcat values of HTHPR25H/Y45Ffor H2O2-dependent oxidation of ABTS and guaiacol are 10-and 100-fold higher, respectively, than those of wild type HTHP (HTHPWT). The kcat/Km values of HTHPR25H/Y45F for both substrates are increased 30-fold relative to that of HTHPWT. Moreover, HTHPR25H/Y45F is capable of promoting catalytic sulfoxidation of thioanisole with H2O2 with a turnover number ca. 2-fold higher than that of HTHPWT. The present findings demonstrate that proximal His ligation to the heme is significantly effective to increase the peroxidase activity in the HTHP matrix.
View MoreZhejiang Kaili Industrial Co., Ltd
Contact:+86-571-85241926
Address:lantian business center,No.18 Moganshan Road
Jiangsu Zhenfang Chemical CO.,LTD.(Suzhou Zhenfang Chemical Factory)
Contact:+86-512-69598882
Address:Room1201, Jiayuan Road No.1018, Xiangcheng District, Suzhou, China
Shanghai Sunwise Chemical Co., Ltd
website:http://www.sunwisechem.com
Contact:86-021-33883180
Address:Room 10E, Building G, Westlink Center, No. 2337 Gudai Road, Minhang District, Shanghai, China PC: 201100
Contact:086-027-83820093
Address:16#luojiashan, wuchang district
KangZhiYuan Pharmaceutical Company Limited
Contact:(Sabrina)86-20-85273232
Address:4th floor, building B, Dadi industry zone, Tangxia, Tianhe, Guangzhou, China
Doi:10.1016/s0020-1693(97)05642-9
(1997)Doi:10.1021/jacs.9b08663
(2019)Doi:10.1039/a900963i
(1999)Doi:10.1021/acs.inorgchem.5b01579
(2015)Doi:10.1016/j.jfluchem.2017.12.001
(2018)Doi:10.1002/hc.10121
(2003)