Hydroxylation Of Naphthalene Research Articles

Colorimetric Assay for Protein Redox Activity – a Complement to Electrochemistry

Oxidoreductases are vital biocatalytic tools for driving redox conversions that are challenging using conventional catalysts. Monooxygenases, an important class of these enzymes, have been the subject of enzyme engineering due to their high activity and versatile substrate scope. Reactions performed by these biocatalysts have long been monitored by a colorimetric method involving the coupling of a dye precursor to naphthalene hydroxylation products generated by the enzyme. Despite the popularity of this method, we found the dye product to be unstable, preventing quantitative readout. By incorporating an extraction step to solubilize the dye produced, we have improved this assay to the point where quantitation of enzyme activity is possible. Further, by incorporating spectral deconvolution, we have, for the first time, enabled independent quantification of the two possible regioisomeric products: 1-naphthol and 2-naphthol. Previously, such analysis was only possible with chromatographic separation, increasing the cost and complexity of analysis. The efficacy of our improved workflow was evaluated by monitoring the activity of a toluene-4-monooxygenase enzyme from Pseudomonas mendocina KR-1. Our colorimetric regioisomer quantification was found to be consistent with chromatographic analysis by HPLC. The development and validation of a quantitative colorimetric assay for monooxygenase activity that enables regioisomeric distinction and quantification represents a significant advance in analytical methods to monitor enzyme activity. By maintaining facile, low-cost, high-throughput readout while incorporating quantification, this assay represents an important alternative to more expensive chromatographic quantification techniques. For the electrochemistry community, the use of monooxygenases or other redox capable enzymes for biocatalysis must be complemented by a toolkit of methods for accurate enzyme activity measurement. Our approach demonstrates that accurate, mixture analysis is possible in a higher throughput using the improved colorimetric method. The relevant assay reaction, the hydroxylation of naphthalene, may be readily incorporated in the future for measurement schemes with other enzymes than the tested toluene-4-monooxygenase, thus enabling opportunities to tune these biocatalysts towards desired activities.

Metagenomics-metabolomics analysis of microbial function and metabolism in petroleum-contaminated soil

Contamination of soil by petroleum is becoming increasingly serious in the world today. However, the research on gene functional characteristics, metabolites and distribution of microbial genomes in oil-contaminated soil is limited. Considering that, metagenomic and metabonomic were used to detect microbes and metabolites in oil-contaminated soil, and the changes of functional pathways were analyzed. We found that oil pollution significantly changed the composition of soil microorganisms and metabolites, and promoted the relative abundance of Pseudoxanthomonas, Pseudomonas, Mycobacterium, Immundisolibacter, etc. The degradation of toluene, xylene, polycyclic aromatic hydrocarbon and fluorobenzoate increased in Xenobiotics biodegradation and metabolism. Key monooxygenases and dioxygenase systems were regulated to promote ring opening and degradation of aromatic hydrocarbons. Metabolite contents of polycyclic aromatic hydrocarbons (PAHs) such as 9-fluoronone and gentisic acid increased significantly. The soil microbiome degraded petroleum pollutants into small molecular substances and promoted the bioremediation of petroleum-contaminated soil. Besides, we discovered the complete degradation pathway of petroleum-contaminated soil microorganisms to generate gentisic acid from the hydroxylation of naphthalene in PAHs by salicylic acid. This study offers important insights into bioremediation of oil-contaminated soil from the aspect of molecular regulation mechanism and provides a theoretical basis for the screening of new oil degrading bacteria.

An Improved Spectrophotometric Method for Toluene-4-Monooxygenase Activity.

Monooxygenases, an important class of enzymes, have been the subject of enzyme engineering due to their high activity and versatile substrate scope. Reactions performed by these biocatalysts have long been monitored by a colorimetric method involving the coupling of a dye precursor to naphthalene hydroxylation products generated by the enzyme. Despite the popularity of this method, we found the dye product to be unstable, preventing quantitative readout. By incorporating an extraction step to solubilize the dye produced, we have improved this assay to the point where quantitation of enzyme activity is possible. Further, by incorporating spectral deconvolution, we have, for the first time, enabled independent quantification of the two possible regioisomeric products: 1-naphthol and 2-naphthol. Previously, such analysis was only possible with chromatographic separation, increasing the cost and complexity of analysis. The efficacy of our improved workflow was evaluated by monitoring the activity of a toluene-4-monooxygenase enzyme from Pseudomonas mendocina KR-1. Our colorimetric regioisomer quantification was found to be consistent with chromatographic analysis by HPLC. The development and validation of a quantitative colorimetric assay for monooxygenase activity that enables regioisomeric distinction and quantification represents a significant advance in analytical methods to monitor enzyme activity. By maintaining facile, low-cost, high-throughput readout while incorporating quantification, this assay represents an important alternative to more expensive chromatographic quantification techniques.

Flexibility Regulation of Loops Surrounding the Tunnel Entrance in Cytochrome P450 Enhanced Substrate Access Substantially

In recent years, the engineering of flexible loops to improve enzyme properties has gained attention in biocatalysis. Herein, we report a loop engineering strategy to improve the stability of the substrate access tunnels, which reveals the molecular mechanism between loops and tunnels. Based on the dynamic tunnel analysis of CYP116B3, five positions (A86, T91, M108, A109, T111) in loops B-B′ and B′-C potentially affecting tunnel frequent occurrence were selected and subjected to simultaneous saturation mutagenesis. The best variant 8G8 (A86T/T91L/M108N/A109M/T111A) for the dealkylation of 7-ethoxycoumarin and the hydroxylation of naphthalene was identified with considerably increased activity (134-fold and 9-fold) through screening. Molecular dynamics simulations showed that the reduced flexibility of loops B-B′ and B′-C was responsible for increasing the stability of the studied tunnel. The redesign of loops B-B′ and B′-C surrounding the tunnel entrance provides loop engineering with a powerful and likely general method to kick on/off the substrate/product transportation.

Engineering substrate recognition sites of cytochrome P450 monooxygenase CYP116B3 from Rhodococcus ruber for enhanced regiospecific naphthalene hydroxylation

In this study, a cytochrome P450 monooxygenase CYP116B3 from Rhodococcus ruber was engineered to convert naphthalene selectively into 1-naphthol. The substrate recognition sites (SRSs) of CYP116B3 were identified using structure-based computational analysis. Subsequently, site-directed and saturation mutagenesis were conducted on SRS1, SRS2, and SRS3. The improved resulting triple mutant (E88C-N199Q-Q209A) was characterized. A final 1-naphthol titer of 8.26 mg/L/h was achieved, which is 14-fold higher than the control. The docking results suggest that the conformational changes produced by directed evolution improved the substrate binding environment. The results presented here hold promise for 1-naphthol production by P450 enzymes.

Selective hydroxylation of naphthalene using the H2O2-dependent engineered P450BM3 driven by dual-functional small molecules

We herein report the H2O2-dependent selective hydroxylation of naphthalene catalyzed by engineered P450BM3 with the assistance of dual-functional small molecules (DFSMs). The mutation at position 268 significantly improved the hydroxylation activity of P450BM3, which is quite different from those engineered P450BM3 peroxygenases and NADPH-dependent P450BM3 mutants previously reported, implicating the unique role of the residue at position 268. This study provides a potential approach to develop the practical hydroxylation biocatalyst of P450s for aromatic hydrocarbons using the DFSM-facilitated P450BM3-H2O2system.

Synthesis of 1-Naphthol by a Natural Peroxygenase Engineered by Directed Evolution.

There is an increasing interest in enzymes that catalyze the hydroxylation of naphthalene under mild conditions and with minimal requirements. To address this challenge, an extracellular fungal aromatic peroxygenase with mono(per)oxygenase activity was engineered to convert naphthalene selectively into 1-naphthol. Mutant libraries constructed by random mutagenesis and DNA recombination were screened for peroxygenase activity on naphthalene together with quenching of the undesired peroxidative activity on 1-naphthol (one-electron oxidation). The resulting double mutant (G241D-R257K) obtained from this process was characterized biochemically and computationally. The conformational changes produced by directed evolution improved the substrate's catalytic position. Powered exclusively by catalytic concentrations of H2 O2 , this soluble and stable biocatalyst has a total turnover number of 50 000, with high regioselectivity (97 %) and reduced peroxidative activity.

Coordination of manganese porphyrins on amino-functionalized MCM-41 for heterogeneous catalysis of naphthalene hydroxylation

The different amounts of [5,10,15,20-tetrakis-(pentafluorophenyl)porphyrin] manganese chloride (TF20PPMnCl) were immobilized on amino-functionalized MCM-41 for catalysis of the hydroxylation of naphthalene. The samples were characterized by X-ray powder diffraction, N2 adsorption/desorption isotherms, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, diffuse reflectance ultraviolet-visible spectroscopy, thermogravimetric and differential scanning calorimetry, and inductively coupled plasma mass spectrometry. The results indicated that the manganese porphyrins were axially coordinated on amino-functionalized MCM-41. The prepared samples showed remarkable catalytic activity in the hydroxylation of naphthalene with meta-chloroperbenzoic acid as the oxidant. The catalyst could be reused several times without loss of its activity.

Peroxygenase activity of cytochrome c peroxidase and three apolar distal heme pocket mutants: hydroxylation of 1-methoxynaphthalene

BackgroundThe cytochrome P450s are monooxygenases that insert oxygen functionalities into a wide variety of organic substrates with high selectivity. There is interest in developing efficient catalysts based on the “peroxide shunt” pathway in the cytochrome P450s, which uses H2O2 in place of O2/NADPH as the oxygenation agent. We report on our initial studies using cytochrome c peroxidase (CcP) as a platform to develop specific “peroxygenation” catalysts.ResultsThe peroxygenase activity of CcP was investigated using 1-methoxynaphthalene as substrate. 1-Methoxynaphthalene hydroxylation was monitored using Russig’s blue formation at standard reaction conditions of 0.50 mM 1-methoxynaphthalene, 1.00 mM H2O2, pH 7.0, 25°C. Wild-type CcP catalyzes the hydroxylation of 1-methoxynaphthalene with a turnover number of 0.0044 ± 0.0001 min-1. Three apolar distal heme pocket mutants of CcP were designed to enhance binding of 1-methoxynaphthalene near the heme, constructed, and tested for hydroxylation activity. The highest activity was observed for CcP(triAla), a triple mutant with Arg48, Trp51, and His52 simultaneously mutated to alanine residues. The turnover number of CcP(triAla) is 0.150 ± 0.008 min-1, 34-fold greater than wild-type CcP and comparable to the naphthalene hydroxylation activity of rat liver microsomal cytochrome P450. While wild-type CcP is very stable to oxidative degradation by excess hydrogen peroxide, CcP(triAla) is inactivated within four cycles of the peroxygenase reaction.ConclusionsProtein engineering of CcP can increase the rate of peroxygenation of apolar substrates but the initial constructs are more susceptible to oxidative degradation than wild-type enzyme. Further developments will require constructs with increased rates and selectivity while maintaining the stability of wild-type CcP toward oxidative degradation by hydrogen peroxide.

Photocatalytic Conversion of Naphthalene to α-Naphthol Using Nanometer-Sized TiO2

The effects of various parameters (co-solvents, electron acceptors, and surface modification) on the direct synthesis of α-naphthol from naphthalene using photocatalytic processes were investigated. The OH radicals generated on UV-illuminated TiO 2 photocatalysts led to the direct hydroxylation of naphthalene to α-naphthol. The addition of Fe 3+ , Fe 2+ , Fe 3+ + H 2 O 2 , and Fe 2+ + H 2 O 2 greatly increases the conversion of naphthalene and the yield of α-naphthol in TiO 2 suspensions. The addition of Fe 3+ + H 2 O 2 to a TiO 2 suspension increased the yield to 22.2%. Surface modified-TiO 2 had a significant influence on the hydroxylation reaction. La-Eu/TiO 2 , La-Y/TiO 2 , H 3 PW 12 O 40 /TiO 2 , H 3 PMo 12 O 40 /TiO 2 , Fe/TiO 2 , Ag/TiO 2 , Cu/TiO 2 , and N/TiO 2 enhanced the conversion and yield more than TiO 2 . Fe/TiO 2 has the highest photocatalytic efficiency among these species. ： 研究了共溶剂、电子受体和表面改性等因素对 TiO 2 光催化萘直接合成 α-萘酚反应的影响. 纳米 TiO 2 催化剂在紫外光照射下产生 •OH, 使得萘羟基化得到 α-萘酚. 在 TiO 2 体系中加入 Fe 3+ , Fe 2+ , Fe 3+ + H 2 O 2 和 Fe 2+ + H 2 O 2 时, 均可有效提高萘转化率和 α-萘酚收率, 其中以体系中加入 Fe 3+ + H 2 O 2 时, α-萘酚收率最大, 为 22.2%. TiO 2 经表面改性后所得样品 La-Eu/TiO 2 , La-Y/TiO 2 , H 3 PW 12 O 40 /TiO 2 , H 3 PMo 12 O 40 /TiO 2 , Fe/TiO 2 , Ag/TiO 2 , Cu/TiO 2 和 N/TiO 2 , 萘转化率和 α-萘酚收率均有所提高, 其中以 Fe/TiO 2 光催化效率最高. The ·OH radicals generated on a UV-illuminated TiO 2 photocatalyst led to the direct hydroxylation of naphthalene to α-naphthol. We investigated the effects of cosolvents, electron acceptors, and surface modification on the direct synthesis of a-naphthol from naphthalene using photocatalytic processes.

Perylenequinone Natural Products: Enantioselective Synthesis of the Oxidized Pentacyclic Core

An enantioselective approach to the perylenequinone core found in the mold perylenequinone natural products is outlined. Specifically, the first asymmetric syntheses of helical chiral perylenequinones absent any additional stereogenic centers are described. Key elements of the synthetic venture include a catalytic enantioselective biaryl coupling, a PIFA-induced naphthalene hydroxylation, and a palladium-mediated aromatic decarboxylation. Transfer of the binaphthalene axial stereochemistry to the perylenequinone helical stereochemistry proceeded with good fidelity. Furthermore, the resultant perylenequinones were shown to possess sufficient atropisomeric stability to be viable intermediates in the biogenesis of the perylenequinone natural products. This stability supports the use of the helical axis as a stereochemical relay in synthesis of the natural products containing additional stereochemical centers.

Hydroxylation of naphthalene by aromatic peroxygenase from Agrocybe aegerita proceeds via oxygen transfer from H2O2 and intermediary epoxidation

Agrocybe aegerita peroxidase/peroxygenase (AaP) is an extracellular fungal biocatalyst that selectively hydroxylates the aromatic ring of naphthalene. Under alkaline conditions, the reaction proceeds via the formation of an intermediary product with a molecular mass of 144 and a characteristic UV absorption spectrum (A(max) 210, 267, and 303 nm). The compound was semistable at pH 9 but spontaneously hydrolyzed under acidic conditions (pH<7) into 1-naphthol as major product and traces of 2-naphthol. Based on these findings and literature data, we propose naphthalene 1,2-oxide as the primary product of AaP-catalyzed oxygenation of naphthalene. Using (18)O-labeled hydrogen peroxide, the origin of the oxygen atom transferred to naphthalene was proved to be the peroxide that acts both as oxidant (primary electron acceptor) and oxygen source.

Mutagenesis of the “Leucine Gate” To Explore the Basis of Catalytic Versatility in Soluble Methane Monooxygenase

Soluble methane monooxygenase (sMMO) from methane-oxidizing bacteria is a multicomponent nonheme oxygenase that naturally oxidizes methane to methanol and can also cooxidize a wide range of adventitious substrates, including mono- and diaromatic hydrocarbons. Leucine 110, at the mouth of the active site in the alpha subunit of the hydroxylase component of sMMO, has been suggested to act as a gate to control the access of substrates to the active site. Previous crystallography of the wild-type sMMO has indicated at least two conformations of the enzyme that have the "leucine gate" open to different extents, and mutagenesis of homologous enzymes has indicated a role for this residue in the control of substrate range and regioselectivity with aromatic substrates. By further refinement of the system for homologous expression of sMMO that we developed previously, we have been able to prepare a range of site-directed mutations at position 110 in the alpha subunit of sMMO. All the mutants (with Gly, Cys, Arg, and Tyr, respectively, at this position) showed relaxations of regioselectivity compared to the wild type with monoaromatic substrates and biphenyl, including the appearance of new products arising from hydroxylation at the 2- and 3- positions on the benzene ring. Mutants with the larger Arg and Trp residues at position 110 also showed shifts in regioselectivity during naphthalene hydroxylation from the 2- to the 1- position. No evidence that mutagenesis of Leu 110 could allow very large substrates to enter the active site was found, however, since the mutants (like the wild type) were inactive toward the triaromatic hydrocarbons anthracene and phenanthrene. Thus, our results indicate that the "leucine gate" in sMMO is more important in controlling the precision of regioselectivity than the sizes of substrates that can enter the active site.

Naphthalene degradation in water by heterogeneous photocatalysis: An investigation of the influence of inorganic anions

In a pollution control context, the degradation of naphthalene in water was performed by photocatalysis in UV-irradiated TiO 2 suspensions. The influence of physicochemical parameters such as concentration, photonic flux, temperature, pH and mass of catalyst has been investigated. An optimum titania concentration was found equal to 2.5 g L −1. This value is identical to that observed in other liquid phase reactions, either in water or in liquid organic phases, confirming that this value depends on the design of the photoreactor (geometry, texture of the catalyst, optical pathway). The almost nil effect of the pH upon the kinetics indicates that protons do not intervene at the limiting step level. It was also confirmed that the kinetics were slightly accelerated by a limited increase in temperature with a small apparent activation energy of reaction equal to 22 kJ mol −1. The presence of common salts generally found in natural waters was followed versus kinetics, including NaCl to simulate the treatment of seawater. It has been found that small amounts of carbonates strongly inhibit naphthalene adsorption and degradation. Hydrogenocarbonates were also found to inhibit naphthalene adsorption at low concentration, but no inhibition was observed at concentrations below 0.3 mol HCO 3 − L −1. Surprisingly, addition of sodium chloride makes the initial reaction faster and more selective. It was interpreted as an enhancement of naphthalene adsorption by sodium chloride. The main intermediates of naphthalene photodegradation have been identified by HPLC–DAD and GC–MS. They result from naphthalene hydroxylation and ring-cleavage by action of oxygenated radicals.

Synthesis and spectroscopic, electrochemical, and catalytic properties of a new manganese porphyrin bearing four positive charges close to the metal

A new Mn-porphyrin bearing four pyridinium substituents bound through their nitrogen atoms on the meso-positions of the tetrapyrrole ring was synthesized in three steps from Zn-β-octaethylporphyrin. It was characterized by elemental analysis, electrospray mass spectrometry, UV–vis and dual polarization mode EPR spectroscopy, and electrochemistry. Electrochemical and EPR studies showed that the Mn-porphyrin prepared by this method existed as a 80/20 Mn(II)/Mn(III) mixture, the redox potential of the Mn(III)/Mn(II) couple being +345 mV (versus SCE, in CH 3CN). It catalyzed alkene epoxidation and alkane hydroxylation by PhIO with characteristics comparable to those of Mn[TDCPP = meso-tetra-(2,6-dichlorophenyl)porphyrin]Cl. It also catalyzed the hydroxylation of anisole, naphthalene and ethylbenzene by H 2O 2 in CH 2Cl 2/CH 3CN, as well as the hydroxylation of the drug diclofenac by oxone in water. It is a new biomimetic catalyst exhibiting two distinctive characteristics: a good solubility in both hydrophobic aprotic solvents and water for pH > 5, and an unusual structure with four positive charges very close to the metallic centre.

Protein engineering of toluene-o-xylene monooxygenase from Pseudomonas stutzeri OX1 for enhanced chlorinated ethene degradation and o-xylene oxidation

Toluene-o-xylene monooxygenase (ToMO) from Pseudomonas stutzeri OX1 has been shown to degrade all chlorinated ethenes individually and as mixtures. Here, DNA shuffling of the alpha hydroxylase fragment of ToMO (TouA) and saturation mutagenesis of the TouA active site residues I100, Q141, T201, F205, and E214 were used to enhance the degradation of chlorinated aliphatics. The ToMO mutants were identified using a chloride ion screen and then were further examined by gas chromatography. Escherichia coli TG1/pBS(Kan)ToMO expressing TouA saturation mutagenesis variant I100Q was identified that has 2.8-fold better trichloroethylene (TCE) degradation activity (apparent Vmax of 1.77 nmol min-1 mg-1 protein-1 vs 0.63 nmol min-1 mg-1 protein-1). Another variant, E214G/D312N/M399V, has 2.5-fold better cis-1,2-dichloroethylene (cis-DCE) degradation activity (apparent Vmax of 8.4 nmol min-1 mg-1 protein-1 vs 3.3 nmol min-1 mg-1 protein-1). Additionally, the hydroxylation regiospecificity of o-xylene and naphthalene were altered significantly for ToMO variants A107T/E214A, T201G, and T201S. Variant T201S produced 2.0-fold more 2,3-dimethylphenol (2,3-DMP) from o-xylene than the wild-type ToMO, whereas variant A107T/E214A had 6.0-fold altered regiospecificity for 2,3-DMP formation. Variant A107T/E214A also produced 3.0-fold more 2-naphthol from naphthalene than the wild-type ToMO, whereas the regiospecificity of variant T201S was altered to synthesize 3.0-fold less 2-naphthol, so that it made almost exclusively 1-naphthol (96%). Variant T201G was more regiospecific than variants A107T/E214A and T201S and produced 100% 3,4-DMP from o-xylene and >99% 1-naphthol from naphthalene. Hence, ToMO activity was enhanced for the degradation of TCE and cis-DCE and for the regiospecific hydroxylation of o-xylene and naphthalene through DNA shuffling and saturation mutagenesis.

Structural and functional characterization of “laboratory evolved” cytochrome P450cam mutants showing enhanced naphthalene oxygenation activity

To elucidate molecular mechanisms for the enhanced oxygenation activity in the three mutants of cytochrome P450cam screened by ‘laboratory evolution’ [Nature 399 (1999) 670], we purified the mutants and characterized their functional and structural properties. The electronic absorption and resonance Raman spectra revealed that the structures of heme binding site of all purified mutants were quite similar to that of the wild-type enzyme, although the fraction of the inactivated form, called “P420,” was increased. In the reaction with H 2O 2, only trace amounts of the naphthalene hydroxylation product were detected by gas chromatography. We, therefore, conclude that the three mutants do not exhibit significant changes in the structural and functional properties from those of wild-type P450cam except for the stability of the axial ligand in the reduced form. The enhanced fluorescence in the whole-cell assay would reflect enhancement in the oxygenation activity below the detectable limit of the gas chromatography and/or contributions of other reactions catalyzed by the heme iron.

Model reaction related to cytochrome P-450: effect of substitution on the rate of naphthalene oxidation

Abstract A kinetic method for measuring the relative rates of hydroxylation of naphthalene derivatives/cyclohexene has been developed. With this technique a linear relationship between the logarithm of the rates of oxidation products and the oxidation potentials of the naphthalene derivatives has been observed. Plots of σ Hammett and σ+ Hammett–Brown with logarithm of relative rates have been linear and shown ρ = −0.98 and ρ+ = −0.58, respectively. This contrast aromatic oxidation in protic solvents in which the oxidation products are naphthoquinones and provides further evidence for the intermediacy of carbocation in the hemin catalyzed hydroxylation of aromatic rings.

Regiospecific naphthalene monohydroxylation by a recombinant yeast producing a P4501A1–yeast reductase fused enzyme

The use of a recombinant yeast producing a P4501A1–yeast reductase fused enzyme for the regiospecific hydroxylation of naphthalene to α-naphthol is reported. During the biotransformation, significant levels of naphthalene and α-naphthol were detected in the cell fraction. Initial reaction rates of up to 23 and 13 μmol/g dry cell weight/h at 5.6 and 11.2 g dcw/l, respectively, were measured. The presence of naphthalene at concentrations above aqueous phase saturation (0.45 mM) as a solid was found to increase activity only marginally while the product, α-naphthol, was found to inhibit hydroxylating activity.

Mechanism of the interaction of Mn tetraazaporphines with peracetic acid: The comparative reactivity of Mn(III) porphinoid complexes in the formation of Mn-oxenes

The mechanism of peracetic acid interaction with Mn(III) complexes of tetra-R-tetra- tert-butyl-tetraazaporphines (RTAPMnCl, R=H, Br, PhSO 2, NO 2) in acetonotrile/acetic acid solutions has been studied. Analysis of the kinetic data of trans-stilbene epoxidation, naphthalene hydroxylation, 1,1-diphenyl-2-picrylhydrazine (DPPH), and tetra-4- tert-butyl-phthalocyanine zinc (PcZn) one-electron oxidations revealed the reversible formation of a two-center molecular “catalyst–oxidant” complex ligated with a molecule of acetic acid { A =[ RTAPMn(AcOOH)(AcOH)](X)}. The subsequent irreversible transformation of A with rate constant k 2 leads to the formation of two high-valent oxometallo species, supposedly [RTAPMn(V)(O)(AcOH)](X) and [ +RTAPMn(IV)(O)(AcOH)](X), which are in equilibrium and show distinct oxidation abilities towards olefin and naphthalene. The Hammett-type dependencies of k 2 and of the rate constant of A formation ( k 1) have been analyzed and compared with those ones determined earlier for Mn(III) meso-tetra(2,6-dichloro-4-R-phenyl)porphyrins (RTDCPPMnCl). The enhanced sensibility of the acceptor properties of Mn ion to electronegative substitution in tetraazaporphine macrocycle is considered to be a reason of the highest catalytic oxidative activity of Mn-tetra-nitro-tetra- tert-butyltetraazaporphine within studied Mn porphinoids.