The halide complexes of myeloperoxidase and the mechanism of the halogenation reactions

Bakkenist, A.R.J.; Boer, J.E.G. De; Plat, H.; Wever, Ron

doi:10.1016/0005-2744(80)90088-1

Cited by 139 publications

(89 citation statements)

References 19 publications

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“…6, both enzymes behave identically for most of the tested parameters, except that recMPO appeared more sensitive to higher temperature (> 60°C) than natural MPO. For both enzymes, however, maximal activity was observed around pH 5.0 in the presence of 200 mM NaC1, in agreement with data from Bakkenist et al (1980),…”

Section: Glu Gly Ala Ala Pro Ala Val Leu Gly Glusupporting

confidence: 91%

Structural and biological properties of human recombinant myeloperoxidase produced by Chinese hamster ovary cell lines

Moguilevsky

Garcia‐Quintana

Jacquet

et al. 1991

European Journal of Biochemistry

124

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The cDNA encoding human myeloperoxidase carries three ATG codons in frame; 144,111 and 66 bp upstream from the proprotein DNA sequence. In order to determine the most efficient signal sequence, three cDNA modules starting at each of the ATG were cloned into an eucaryotic expression vector and stably expressed in Chinese hamster ovary cell lines. In all three cases, recombinant human myeloperoxidase (recMPO) was secreted into the culture medium of transfected cells, indicating that each of the signal peptides functions efficiently. One of the recombinant cell lines, which was amplified using methotrexate, overexpresses enzymatically active recMPO up to 6 pg * ml-' * day-'. The recombinant product was purified by a combination of ion-exchange and metalchelate chromatography, and characterized in terms of molecular mass, amino-terminal amino acid analysis, glycosylation, physicochemical properties and biological activity. The data show that recMPO is secreted essentially as a monomeric, heme-containing, single-chain precursor of 84 kDa which exhibits peroxidase activity. Aminoterminal analysis indicated that cleavage of the signal peptide occurs between amino acids 48 and 49. In addition, recMPO appeared to be glycosylated up to the last stage of sialylation, to an extent similar to that of the natural enzyme. Specific activity measurements as well as stability data, in various pH, temperature, ionic strength and reducing conditions, indicated that the recombinant single-chain enzyme behaves essentially in the same way as the natural two-chain molecule. Finally, recMPO was shown to exert potent cytotoxicity towards Escherichiu coli when provided with its physiological substrates, i. e. hydrogen peroxide and chloride ions.

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Section: Glu Gly Ala Ala Pro Ala Val Leu Gly Glusupporting

confidence: 91%

Structural and biological properties of human recombinant myeloperoxidase produced by Chinese hamster ovary cell lines

Moguilevsky

Garcia‐Quintana

Jacquet

et al. 1991

European Journal of Biochemistry

124

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“…In contrast, when the Cl-concentration is fixed and the HzOz concentration is increased, the pH optimum shifts to lower pH values ( fig.3B). Similar kinetics were also observed for myeloperoxidase of neutrophils [ 151. It is interesting to note that the pH optima at the substrate concentrations used are shifted by 0.8 pH unit to more acid pH compared to those of myeloperoxidase [16]. The rate of chlorination of monochlorodimedon at its optimum pH of 5.2 (fig3A) is 42 nmol/min.…”

Section: Methodsmentioning

confidence: 93%

Human eosinophil peroxidase: a novel isolation procedure, spectral properties and chlorinating activity

1981

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“…The ABTS and guaiacol activity assays were started by the addition of H 2 O 2 . We decided not to explore the kinetic parameter (V max and K m ) values in detail considering the complex kinetic behavior of MPO (28).…”

mentioning

confidence: 99%

“…After correction for volume changes the dissociation constants were calculated from saturation curves of the chloride-induced spectral changes (28). Binding studies were performed on an Aminco DW2000 spectrophotometer and a Cary 50 Biospec spectrophotometer.…”

mentioning

confidence: 99%

The Sulfonium Ion Linkage in Myeloperoxidase

Kooter¹,

Moguilevsky²,

Bollen³

et al. 1999

Journal of Biological Chemistry

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The heme group of myeloperoxidase is covalently linked via two ester bonds to the protein and a unique sulfonium ion linkage involving Met 243 . Mutation of Met 243 into Thr, Gln, and Val, which are the corresponding residues of eosinophil peroxidase, lactoperoxidase, and thyroid peroxidase, respectively, and into Cys was performed. The Soret band in the optical absorbance spectrum in the oxidized mutants is now found at approximately 411 nm. Both the pyridine hemochrome spectra and resonance Raman spectra of the mutants are affected by the mutation. In the Met 243 mutants the affinity for chloride has decreased 100-fold. All mutants have lost their chlorination activity, except for the M243T mutant, which still has 15% activity left. By Fourier transform infared difference spectroscopy it was possible to specifically detect the 13 CD 3 -labeled methionyl sulfonium ion linkage. We conclude that the sulfonium ion linkage serves two roles. First, it serves as an electron-withdrawing substituent via its positive charge, and, second, together with its neighboring residue Glu 242 , it appears to be responsible for the lower symmetry of the heme group and distortion from the planar conformation normally seen in heme-containing proteins.In the family of mammalian peroxidases, myeloperoxidase (MPO) 1 is an extraordinary peroxidase. First of all, the enzyme is the only mammalian peroxidase known to peroxidize chloride to hypochlorous acid at a substantial rate. Secondly, MPO differs in its spectroscopic characteristics by its unusual redshifted Soret band in the optical absorbance as well in its pyridine hemochrome spectrum, its complicated resonance Raman spectrum, and its inverted sign pattern of the Soret band in the MCD spectrum (1-6). Those differences have been attributed to the special nature or structure of the heme group in MPO. Because this heme is covalently bound to the protein, characterization of this chromophore has been difficult. Based on different spectroscopic techniques, a formyl-containing heme a, a chlorin, and a heme b prosthetic group have been proposed in the past (3,5,(7)(8)(9).Although the enzyme differs in spectroscopic and catalytic properties, the homology between MPO and the other mammalian peroxidases is high. MPO shares respectively 70, 61, and 47% identical residues with eosinophil peroxidase (EPO), lactoperoxidase (LPO), and thyroid peroxidase (TPO) (10 -12), and an even higher homology can be found among the residues in the active site. MPO is the only mammalian peroxidase for which a crystal structure is known, at 2.3 Å resolution (13). The structural data for human MPO suggested that three heme substituents form covalent bonds with amino acid side chains in the protein. Two ester bonds were claimed to be present, between modified methyl groups on pyrrole rings A and C and the amino acids Glu 242 and Asp 94 . In a recent study, we have provided the first direct evidence by FTIR difference spectroscopy that ester bonds link the heme groups in all mammalian peroxidases via the conser...

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The halide complexes of myeloperoxidase and the mechanism of the halogenation reactions

Cited by 139 publications

References 19 publications

Structural and biological properties of human recombinant myeloperoxidase produced by Chinese hamster ovary cell lines

Structural and biological properties of human recombinant myeloperoxidase produced by Chinese hamster ovary cell lines

Human eosinophil peroxidase: a novel isolation procedure, spectral properties and chlorinating activity

The Sulfonium Ion Linkage in Myeloperoxidase

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