Microperoxidase 11(MP 11) was immobilized on the surface of a silanized glass carbon electrode by means of the covalent bond with glutaraldehyde. The measurements of cyclic voltammetry demonstrated that the formal r...Microperoxidase 11(MP 11) was immobilized on the surface of a silanized glass carbon electrode by means of the covalent bond with glutaraldehyde. The measurements of cyclic voltammetry demonstrated that the formal redox potential of immobilized MP 11 was -170 mV, which is significantly more positive than that of MP 11 in a solution or immobilized on the surface of electrodes prepared with other methods. This MP 11 modified electrode showed a good electrocatalytic activity and stability for the reduction of oxygen and hydrogen peroxide.展开更多
Peroxidase activity greatly impacts the maintenance of flee radical homeostasis, and can prevent or treat diseases related to free radicals. Microperoxidase-11（MP-11 ） is created via hydrolysis of cytochrome c iron-...Peroxidase activity greatly impacts the maintenance of flee radical homeostasis, and can prevent or treat diseases related to free radicals. Microperoxidase-11（MP-11 ） is created via hydrolysis of cytochrome c iron-porphyrin complexes. In these complexes, the heme iron is penta-coordinate with histidine and exhibits excellent antioxidant activity when decomposing hydrogen peroxide. In this study, we screened the Ph.D.-7 and Ph.D.-12 phage display＇ peptide libraries and obtained ten small peptide ligands of deuterohemin（the vinyl groups of oxidized heme）. Among these polypeptides, DhHP-7P1, 12P1, 12P2 and 12P6 have good enzymatic activity compared with MP-11, and exhibit activities up to 50% of MP-11. Based on the screened sequences, we designed a series of artificial microperoxidases and determined that a higher peroxidase activity could be achieved with an enzymatic active site containing a second site of histidine residue spaced between two arginine residues with an interval of two amino acids（Dh-XHRXXR）.展开更多
The interaction of MP 11 as a model of antioxidatase enzymes with La 3+ was investigated. It was found that La 3+ can increase in the non planarity of heme and the content of α helix and β turn conformat...The interaction of MP 11 as a model of antioxidatase enzymes with La 3+ was investigated. It was found that La 3+ can increase in the non planarity of heme and the content of α helix and β turn conformations of the MP 11 molecule. The change in the secondary structure of the MP 11 molecule can increase in the exposure extent of heme to the solution. Therefore, the electrochemical reaction of MP 11 is promoted and the electrocatalytic activity to the reduction of H 2O 2 is increased. The results are consistent with that for the interaction of peroxidases(POD), one of the antioxidatase enzymes, obtained in the living plant experiments at low concentration of La 3+ .展开更多
It was found that microperoxidase-11 (MP-if) can undergo photoreduction at the bareroughened silver electrode. No photoreduction happens at the roughened silver electrodemodified with mercaptoundecanoic carboxylic aci...It was found that microperoxidase-11 (MP-if) can undergo photoreduction at the bareroughened silver electrode. No photoreduction happens at the roughened silver electrodemodified with mercaptoundecanoic carboxylic acid/poly-lysine. The photoreduction mechanismis discussed.展开更多
基金Supported by"973" Project(No. G2 0 0 0 0 2 6 4 0 8) the National Natural Science Foundation of China(No.2 99730 15 ) the Natural Science Foundation of Heilongjiang Province(B2 0 0 0 - 0 6 ) and the Natural Science Foundation of Eduction Comm it-
文摘Microperoxidase 11(MP 11) was immobilized on the surface of a silanized glass carbon electrode by means of the covalent bond with glutaraldehyde. The measurements of cyclic voltammetry demonstrated that the formal redox potential of immobilized MP 11 was -170 mV, which is significantly more positive than that of MP 11 in a solution or immobilized on the surface of electrodes prepared with other methods. This MP 11 modified electrode showed a good electrocatalytic activity and stability for the reduction of oxygen and hydrogen peroxide.
基金Supported by the National Natural Science Foundation of China（No. 31401086）, the Program of the Science and Technology Development of Jilin Province, China（No.20150520157JH）, the Postdoctoral Science Foundation of China（No.2015M581398） and the Special Project for Health of Jilin Province, China（No.2018SCZWSZX-037）.
文摘Peroxidase activity greatly impacts the maintenance of flee radical homeostasis, and can prevent or treat diseases related to free radicals. Microperoxidase-11（MP-11 ） is created via hydrolysis of cytochrome c iron-porphyrin complexes. In these complexes, the heme iron is penta-coordinate with histidine and exhibits excellent antioxidant activity when decomposing hydrogen peroxide. In this study, we screened the Ph.D.-7 and Ph.D.-12 phage display＇ peptide libraries and obtained ten small peptide ligands of deuterohemin（the vinyl groups of oxidized heme）. Among these polypeptides, DhHP-7P1, 12P1, 12P2 and 12P6 have good enzymatic activity compared with MP-11, and exhibit activities up to 50% of MP-11. Based on the screened sequences, we designed a series of artificial microperoxidases and determined that a higher peroxidase activity could be achieved with an enzymatic active site containing a second site of histidine residue spaced between two arginine residues with an interval of two amino acids（Dh-XHRXXR）.
文摘The interaction of MP 11 as a model of antioxidatase enzymes with La 3+ was investigated. It was found that La 3+ can increase in the non planarity of heme and the content of α helix and β turn conformations of the MP 11 molecule. The change in the secondary structure of the MP 11 molecule can increase in the exposure extent of heme to the solution. Therefore, the electrochemical reaction of MP 11 is promoted and the electrocatalytic activity to the reduction of H 2O 2 is increased. The results are consistent with that for the interaction of peroxidases(POD), one of the antioxidatase enzymes, obtained in the living plant experiments at low concentration of La 3+ .
文摘It was found that microperoxidase-11 (MP-if) can undergo photoreduction at the bareroughened silver electrode. No photoreduction happens at the roughened silver electrodemodified with mercaptoundecanoic carboxylic acid/poly-lysine. The photoreduction mechanismis discussed.
