[36] Peroxidative activities of hemoglobin and hemoglobin derivatives

Everse, Johannes; Johnson, Maria C.; Marini, Mario

doi:10.1016/0076-6879(94)31038-6

Cited by 104 publications

(63 citation statements)

References 23 publications

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“…These findings concur with earlier observations of Lee and Choi (2007) Peroxidasic activity is a well-known property of hemoglobin (Everse et al, 1990). Choi and co-workers (Choi et al, 2000) showed for normoxic conditions that C. riparius…”

Section: Discussionsupporting

confidence: 93%

Assessment of the effect of nanomaterials on sediment-dwelling invertebrate Chironomus tentans larvae

Oberholster

Musee

Botha

et al. 2011

Ecotoxicology and Environmental Safety

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Section: Discussionsupporting

confidence: 93%

Assessment of the effect of nanomaterials on sediment-dwelling invertebrate Chironomus tentans larvae

Oberholster

Musee

Botha

et al. 2011

Ecotoxicology and Environmental Safety

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“…The extract was then centrifuged at 10,000 rpm for 30 min and the supernatant was saved for estimation of antioxidant enzymes. The activity of GPX was measured by the method of Everse et al (1994). The reaction mixture was composed of 50 µL of supernatant, 50 µL of d/w, 3.75 mL of sodium phosphate buffer, 100 µL of H 2 O 2 , and 100 µL of guaiacol.…”

Section: Extraction and Estimation Of Antioxidant Enzymesmentioning

confidence: 99%

Oxidative stress and antioxidant defense mechanism in mung bean seedlings after lead and cadmium treatments

Hassan¹,

Mansoor

2014

Turk J Agric For

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“…1) and can catalyze various oxidation reactions using H 2 O 2 (13)(14)(15)(16)(17)(18)(19). However, Mb reacts with H 2 O 2 much slower (ϳ10 2 M -1 s -1 ) than peroxidases (ϳ10 7 …”

mentioning

confidence: 99%

Effects of the Location of Distal Histidine in the Reaction of Myoglobin with Hydrogen Peroxide

Matsui¹,

Ozaki²,

Liong³

et al. 1999

Journal of Biological Chemistry

185

249

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To clarify how the location of distal histidine affects the activation process of H 2 O 2 by heme proteins, we have characterized reactions with H 2 O 2 for the L29H/ H64L and F43H/H64L mutants of sperm whale myoglobin (Mb), designed to locate the histidine farther from the heme iron. Whereas the L29H/H64L double substitution retarded the reaction with H 2 O 2 , an 11-fold rate increase versus wild-type Mb was observed for the F43H/ H64L mutant. The V max values for 1-electron oxidations by the myoglobins correlate well with the varied reactivities with H 2 O 2 . The functions of the distal histidine as a general acid-base catalyst were examined based on the reactions with cumene hydroperoxide and cyanide, and only the histidine in F43H/H64L Mb was suggested to facilitate heterolysis of the peroxide bond. The x-ray crystal structures of the mutants confirmed that the distal histidines in F43H/H64L Mb and peroxidase are similar in distance from the heme iron, whereas the distal histidine in L29H/H64L Mb is located too far to enhance heterolysis. Our results indicate that the proper positioning of the distal histidine is essential for the activation of H 2 O 2 by heme enzymes.Peroxidase is a heme enzyme that catalyzes 1-electron oxidations of a variety of substrates (1, 2). The ferric enzyme is oxidized by H 2 O 2 to yield a ferryl porphyrin cation radical (Fe IV ϭO Por . ϩ ) known as compound I in the first step of the catalytic cycle (3). Compound I is reduced to the ferric state through a ferryl species (Fe IV ϭO Por), so-called compound II, by two sequential 1-electron oxidations of substrates. The invariant histidine in the distal heme pocket (1-6) is a critical residue for peroxidases, and its replacement by aliphatic residues retards compound I formation by 5ϳ6 orders of magnitude (7-9). As shown in Scheme I, the distal histidine is believed to function (i) as a general base to accelerate binding of H 2 O 2 to the ferric heme iron by deprotonating the peroxide and (ii) as a general acid to facilitate the heterolytic cleavage of the O-O bond of a plausible Fe III ⅐OOH complex by protonating the terminal oxygen atom (10). The charge separation in heterolysis is suggested to be also enhanced by a positively charged distal arginine (Scheme I), whose substitution results in 2 orders of magnitude slower formation of compound I (10 -12).Myoglobin (Mb), 1 a carrier of molecular oxygen, similarly possesses a distal histidine (His-64) in the heme pocket ( Fig. 1 might be partly due to the malfunction of the distal histidine as a general acid-base catalyst and the absence of the distal arginine. Whereas the distal histidine in peroxidase is suggested to raise the basicity of imidazole by a hydrogen bond with the adjacent asparagine (20, 21), the absence of the hydrogen bond in Mb (13, 14) is indicative of less basicity of its distal histidine. Furthermore, wild-type Mb cleaves the O-O bond of the heme-bound peroxide not only heterolytically, but also homolytically to give Mb-II and a hydroxy radical as shown in Scheme...

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[36] Peroxidative activities of hemoglobin and hemoglobin derivatives

Cited by 104 publications

References 23 publications

Assessment of the effect of nanomaterials on sediment-dwelling invertebrate Chironomus tentans larvae

Assessment of the effect of nanomaterials on sediment-dwelling invertebrate Chironomus tentans larvae

Oxidative stress and antioxidant defense mechanism in mung bean seedlings after lead and cadmium treatments

Effects of the Location of Distal Histidine in the Reaction of Myoglobin with Hydrogen Peroxide

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