ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionEvaluation of Norcarane as a Probe for Radicals in Cytochrome P450- and Soluble Methane Monooxygenase-Catalyzed Hydroxylation Reactions [J. Am. Chem. Soc.2002, 124, 6879−6886].Martin Newcomb, Runnan Shen, Yun Lu, Minor J. Coon, Paul F. Hollenberg, Daniel A. Kopp, and Stephen J. LippardCite this: J. Am. Chem. Soc. 2006, 128, 4, 1394Publication Date (Web):January 6, 2006Publication History Published online6 January 2006Published inissue 1 February 2006https://doi.org/10.1021/ja0599216Copyright © 2006 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views412Altmetric-Citations4LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (20 KB) Get e-Alerts Get e-Alerts

Intramolecular kinetic isotope effects (KIEs) were determined for cytochrome P450-catalyzed hydroxylation reactions of methyl-dideuterated trans-2-phenylcyclopropylmethane-d2 (1-d2), which gives two products from oxidation of the methyl group, trans-2-phenylcyclopropylmethanol (2) and 1-phenyl-3-buten-1ol (3). In oxidations of each enantiomer of 1-d2 with three P450 enzymes (CYP2B1, CYPDelta2E1, and CYPDelta2E1 T303A), the apparent intramolecular KIEs were different for products 2 and 3 in all cases and different for each enzyme-substrate combination. In oxidations of each enantiomer of undeuterated 1-d0 and trideuteriomethyl 1-d3 by CYP2B1 and CYPDelta2E1, the ratio of products 2/3 decreased for 1-d3 in comparison to 1-d0 in all cases. The results require multiple pathways for P450-catalyzed hydroxylation and are consistent with the "two-oxidants" model, where hydroxylation is effected by both the hydroperoxy-iron species and the iron-oxo species. The results are not consistent with predictions of the "two-states" model for P450-catalyzed hydroxylations, where oxidations occur from a low-spin state and a high-spin state of iron-oxo.

Norcarane was employed as a mechanistic probe in oxidations catalyzed by hepatic cytochome P450 enzymes and by the soluble methane monooxygenase (sMMO) enzyme from Methylococcus capsulatus (Bath). In all cases, the major oxidation products (>75%) were endo- and exo-2-norcaranol. Small amounts of 3-norcaranols, 2-norcaranone, and 3-norcaranone also formed. In addition, the rearrangement products (2-cyclohexenyl)methanol and 3-cycloheptenol were detected in the reactions, the former possibly arising from a radical intermediate and the latter ascribed to a cationic intermediate. The formation of the cation-derived rearrangement product is consistent with one or more reaction pathways and is in accord with the results of previous probe studies with the same enzymes. The appearance of the putative radical-derived rearrangement product is in conflict with other mechanistic probe results with the same enzymes. The unique implication of a discrete radical intermediate in hydroxylations of norcarane may be the consequence of a minor reaction pathway for the enzymes that is not manifest in reactions with other probes. Alternatively, it might reflect a previously unappreciated reactivity of norcaranyl cationic intermediates, which can convert to (2-cyclohexenyl)methanol. We conclude that generalizations regarding the intermediacy of radicals in P450 and sMMO enzyme-catalyzed hydroxylations based on the norcarane results should be considered hypothetical until the origin of the unanticipated results can be determined.

A bacterium, Bacillus E?53 was screened from soil, which preferentially hydrolyzed S (+) isomer of the racemic naproxen methyl ester to produce S (+) naproxen. The strain showed higher specificity of resolution about 87% ee. The optimal medium for producing lipase contained 0.5% of glucose, 0.5% of peptone and 0.2% of yeast extract. 0.5% of olive oil could induce lipase production.

描述了在批式反应器和连续流搅拌反应器 （ CSTR）中酶动力学拆分对映异构体的不同之处。从宏观反应器平衡角度 ,推导出了在 CSTR反应器中不同于在批式反应器中的一定酶立体选择性 （ E）下 ,底物或产物的对映体过量值 （ ees或 eep）与反应的转化率 （ξ）之间关系的定量关系式。并通过商品脂肪酶 （ candidarugosa lipase）及芽孢杆菌 E- 53脂肪酶催化的萘普生甲酯的不对称水解反应得到了证实。分别在批式反应器和 CSTR反应器中进行萘普生的酶法拆分 ,在一定转化率下 ,批式反应器中得到的底物及产物的对映体过量值高于 CSTR反应器中得到的结果。

Oxidation of the mechanistic probes trans, trans-2-methoxy-3-phenylmethylcyclopropa and methylcubane by six cytochrome P450 isozymes has been studied. The probes differentiate between radical and cationic species in that different structural rearrangements occur for the two types of intermediates. The P450 isozymes are the phenobarbital-inducible hepatic isozymes P450 2B1 (from rat) and P450 2B4 (from rabbit), the expressed truncated isozymes P450 Delta 2B4 and P450 Delta 2E1 (ethanol-inducible, from rabbit), and mutants of the latter two in which an active site threonine was replaced with alanine, Delta 2B4 T302A, and Delta 2E1 T303A. Cationic rearrangement products were found from both probes. Oxidations of trans, trans-2-methoxy-3-phenylmethylcyclopropane gave small amounts of radical-derived rearrangement products indicating that hydroxylation occurs via insertion reactions with transition state lifetimes in the 80-200 fs range. A mechanistic description of cytochrome P450-catalyzed hydroxylations that is in accord with the present and previous radical probe results is presented. This description incorporates the recent demonstrations that two electrophilic oxidants are produced in the natural course of P450 oxidation reactions and that both electrophilic oxidant forms can effect hydroxylation reactions. Following production of a peroxo-iron species, protonation gives a hydroperoxo-iron species. Protonation of the hydroperoxo-iron species gives an iron-ore species and water. Hydroxylations by both the hydroperoxo-iron and iron-ore species occur by insertion reactions. The hydroperoxo-iron species inserts the elements of OH+ producing protonated alcohol products that can react in solvolysis-type reactions to give cationic rearrangement products. The iron-ore species reacts by insertion of an oxygen atom.

A stereoselective hydrolysis of the racemic naproxen methyl ester by immobilized lipase from Candida rugosa in a low aqueous-organic biphase system was studied. Support polar, water content, the logP value of organic phase and product inhibition effected the activity of immobilized enzyme. According to these reaction conditions, a low aqueous-organic biphase system for the continuous production of (S)-(+)-Naproxen was developed. The reaction was carried out in a continuous-flow closed-loop 50 mL stirred bioreactor packed with YWG-C6H5, a poorly polar synthetic support on which the lipase had been immobilized by adsorption. The aqueous phase was permanently remained in the reactor associated with the immobilized enzyme particles; the organic phase containing substrate was pumped through this reactor and emerged with the products. The continous-flow stirred bioreactor containing 75 mg lipase was allowed to operate continuously for 60 days at 30 degrees C with a 25% loss of activity, 900 mg of (S)-(+)-Naproxen (eep 95%) were producted.

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTCationic Species Can Be Produced in Soluble Methane Monooxygenase-Catalyzed Hydroxylation Reactions; Radical Intermediates Are Not FormedSeung-Yong Choi, Philip E. Eaton, Daniel A. Kopp, Stephen J. Lippard, Martin Newcomb, and Runnan ShenView Author Information Department of Chemistry, Wayne State University Detroit, Michigan 48202 Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 Department of Chemistry, University of Chicago Chicago, Illinois 60637 Cite this: J. Am. Chem. Soc. 1999, 121, 51, 12198–12199Publication Date (Web):December 10, 1999Publication History Received8 September 1999Published online10 December 1999Published inissue 1 December 1999https://pubs.acs.org/doi/10.1021/ja993259uhttps://doi.org/10.1021/ja993259urapid-communicationACS PublicationsCopyright © 1999 American Chemical SocietyRequest reuse permissionsArticle Views303Altmetric-Citations53LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Alcohols,Organic reactions,Oxidation,Peptides and proteins,Probes Get e-Alerts

Intermediate compound II and III may be formed as a result of the reaction of horseradish peroxidase with H2O2. From the UV spectra, we can see that the stability of the intermediate compounds is worse in reverse micelle than that in aqueous solution. With the increase of the water content, the stability of intermediate compounds gets better, this means that the characteristic of the water in the water pool is near that of bulk water. The results of the stopped-flow experiments show that the formation rate constant and V-initial of intermediate compound in reverse microemulsion are bigger than that in aqueous solution. However, within the longer reaction time, the disappearance of the intermediate compound appears early in reverse microemulsion than that in aqueous solution. These results are in agreement with the result of the UV experiments.

Annals of the New York Academy of SciencesVolume 864, Issue 1 p. 609-615 Methanol Biosynthesis by Methanotrophic Bacterial Cells: Effects of Various Immobilization Methods on Biocatalytic Activity of Immobilized Cellsa CHILI YU, CHILI YU State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorSHIWEN XIA, SHIWEN XIA State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorRUNNAN SHEN, RUNNAN SHEN State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorCHUNGU XIA, CHUNGU XIA State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorSHUBEN LI, SHUBEN LI State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this author CHILI YU, CHILI YU State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorSHIWEN XIA, SHIWEN XIA State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorRUNNAN SHEN, RUNNAN SHEN State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorCHUNGU XIA, CHUNGU XIA State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorSHUBEN LI, SHUBEN LI State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this author First published: 07 February 2006 https://doi.org/10.1111/j.1749-6632.1998.tb10390.xCitations: 10 a This research was supported by the National Natural Scientific Foundation of China (Grant Nos. 29471030 and 29773056). Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume864, Issue1ENZYME ENGINEERING XIVDecember 1998Pages 609-615 RelatedInformation

Annals of the New York Academy of SciencesVolume 864, Issue 1 p. 616-620 Extraction and Some Properties of Soluble Methane Monooxygenase of Methylosinus trichosporium IMV 3011a CHILI YU, CHILI YU State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorRUNNAN SHEN, RUNNAN SHEN State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorCHUNGU XIA, CHUNGU XIA State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorSHUBEN LI, SHUBEN LI State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this author CHILI YU, CHILI YU State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorRUNNAN SHEN, RUNNAN SHEN State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorCHUNGU XIA, CHUNGU XIA State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorSHUBEN LI, SHUBEN LI State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this author First published: 07 February 2006 https://doi.org/10.1111/j.1749-6632.1998.tb10391.x a This research was supported by the National Natural Scientific Foundation of China (Grant Nos. 29471030 and 29773056). Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume864, Issue1ENZYME ENGINEERING XIVDecember 1998Pages 616-620 RelatedInformation

A Methylomonas (strain GYJ3) isolated in our laboratory was identified as the type II methanotroph on the basis of the intractytoplasmic membrane of the ultrastructure. The optimal culture conditions for production of the soluble from of methane monooxygenase (MMO) were determined, in which the ratio of methane to air in atmosphere was 2 to 1 and Cu2+ concentration was 1.5 mumol/L. The biodegradation of trichoroethylene(TCE) by the resting cells of the strain GYJ3 was studied. All experiments were performed with cells grown under above conditions and thus expressing soluble MMO. This results showed that TCE at the high concentration of 30 mg/L did not inhibit to the enzymes in the cells. Addition of formate increased the initial specific TCE degradation rates. The product of TCE oxidation was found to be toxic to the cells. The degree of inactivation of MMO was proportional to the amount of TCE degraded. The TCE degradation capacities(Tc) of resting cells was determined. In no-formate and formate-fed experiments, the TCE degradation capacities were found to be 0.0778 and 0.0851 mg of TCE/mg of dry cell, respectively.

Annals of the New York Academy of SciencesVolume 864, Issue 1 p. 565-569 Effect of Exogenous Electron Donors and Water-Soluble Polymers on the Propene-Epoxidizing Activity of Methylomonas Z201 Cells SHIWEN XIA, SHIWEN XIA Bioactive Materials Research Laboratory; Institute of Molecular Biology; Nankai University; Tianjin 300071, ChinaSearch for more papers by this authorYAOTING YU, YAOTING YU Bioactive Materials Research Laboratory; Institute of Molecular Biology; Nankai University; Tianjin 300071, ChinaSearch for more papers by this authorLI YUCHI, LI YUCHI State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorRUNNAN SHEN, RUNNAN SHEN State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorSHUBEN LI, SHUBEN LI State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this author SHIWEN XIA, SHIWEN XIA Bioactive Materials Research Laboratory; Institute of Molecular Biology; Nankai University; Tianjin 300071, ChinaSearch for more papers by this authorYAOTING YU, YAOTING YU Bioactive Materials Research Laboratory; Institute of Molecular Biology; Nankai University; Tianjin 300071, ChinaSearch for more papers by this authorLI YUCHI, LI YUCHI State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorRUNNAN SHEN, RUNNAN SHEN State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this authorSHUBEN LI, SHUBEN LI State Key Laboratory of Oxosynthesis and Selective Oxidation; Lanzhou Institute of Chemical Physics; Chinese Academy of Sciences; Lanzhou 730000, ChinaSearch for more papers by this author First published: 07 February 2006 https://doi.org/10.1111/j.1749-6632.1998.tb10382.xCitations: 1Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat REFERENCES 1 Hou, C. T. 1984. Propene oxide production by immobilized whole cells of Methylosinus sp. CRL31 in a gas-solid bioreactor. Appl. Microbiol. Biotechnol. 19: 1–4. 2 Kovalenko, G. A. & V. D. Sokolovskii. 1992. Epoxidization of propene by microbial cells immobilized on inorganic supports. Biotechnol. Bioeng. 39: 522–528. 3 Xia, S. W., L. Yuchi & S. B. Li. 1996. Immobilized Methylomonas Z201 cells: MMO activity and stability. Chin. J. Mol. Catal. 10: 251–256. 4 Wang, F. L., J. Zhen, F. Wang et al. 1993. Isolation and characteristics of a methanotrophic strain with propene-epoxidizing activity. Acta Microbiol. Sin. 33: 129–134. 5 Leak, D. J. & H. Dalton. 1983. In vivo studies of primary alcohols, aldehydes, and carboxylic acids as electron donors for the methane monooxygenase in a variety of methanotrophs. J. Gen. Microbiol. 129: 3484–3497. 6 Shen, R. N., L. Yuchi & S. B. Li. 1996. Effects of exogenous electron donors on epoxidization of propene catalyzed by methane monooxygenase of Methylomonas GYJ3. Chin. J. Biotechnol. 12: 322–326. 7 Stanley, S. H. & H. Dalton. 1993. The biotransformation of propene to propene oxide by Methylococcus capsulatus (bath): 1. Optimization of rates. Biocatalysis 6: 163–175. 8 Hamstra, R. S., M. R. Murris & J. Tramper. 1987. The influence of immobilization and reduced water activity on gaseous-alkene oxidation by Mycobacterium PY1 and Xanthobacter PY2 in a gas-solid bioreactor. Biotechnol. Bioeng. 29: 884–891. Citing Literature Volume864, Issue1ENZYME ENGINEERING XIVDecember 1998Pages 565-569 ReferencesRelatedInformation

The hydroxylase and reductase components of a soluble methane monooxygenase from type I methanotrophs--Methylomonas sp. GYJ3--were purified by a multiple-step LC procedure. The hydroxylase (approximately 240 kDa, determined by an HPLC-size exclusion chromatography method) has three subunits with molecular masses of 56, 43, and 27 kDa, suggesting that the enzyme has an (alphabeta gamma)2 subunit structure. The HPLC method was developed to purify the hydroxylase component, and the purified protein has a specific activity of 541 nmol propene oxide x mg(-1) protein x min(-1), which is two times the specific activity of the protein purified by the two-step LC procedure. The iron content in the hydroxylase purified by the two-step LC procedure is 2.1 mol of Fe per mole of protein, but the iron content in the protein by the HPLC procedure is 3.78 mol of Fe per mole of protein. The diversity of iron contents in this protein is due mainly to the use of different purification methods. The reductase has a molecular mass of 42 kDa. The UV-VIS spectrum of the protein is similar to that of proteins from other methanotrophs, suggesting that the protein contains a FAD cofactor and a [2Fe-2S] center. The partially purified component B stimulated the MMO activity of the hydroxylase and reductase system by 40-fold.

XAFS studies on this non-heme chloroperoxidase reveal that its Fe core is in a saturated six-coordinate, octahedral environment with four planer N atoms and two axial S atoms. The active site is very similar to Fe porphyrine center in P450 oxidase, but the coordinated N atoms come from amino acids of polypeptides or other molecules, but not porphyrin.

The role of three components of methane monooxygenase (MMO) in catalytic cycle was studied. The hydroxylase, regulatory protein B and reductase components were found to be incapable of catalyzing reaction alone. The hydroxylase can be reduced to different reduced state. Only the reduced hydroxylase can catalyze propene epoxidation. This provides the evidence that the active site of the MMO is located in the hydroxylase component. The iron content of the hydroxylase is related to the MMO activity suggesting that the iron cluster might be the active site of hydroxylase. The reductase is yellow with maximum absorption at 460 nm. The 460 nm peak is abolished by adding NADH. This component is responsible for the transfer of reducing equivalents from NADH to hydroxylase. The possible order of electron flow is NADH��reductase��hydroxylase. The reductase possibly functions as a 2 e-1/1 e-1 transferase, splitting electron pairs from NADH to hydroxylase via the one-electron-carrying Fe2S2 center. The partially purified regulatory protein, which plays a role as an electron transfer in the catalytic cycle, could increase the MMO activity of the hydroxylase and reductase system by 40 times.

The catalytic performance of methane monooxygenase (MMO) from Methylomonas sp. GYJ3 was studied. The results showed that the efficient propene epoxidation coupling with NADH oxidation requires all three components of the MMO. The MMO activity of the reconstituted system reached 342 nmol/(mg��min) when the molar ratio of hydroxylase, regulatory protein B and reductase was 1 : 1.7 : 2.0. The optimum pH range was 6.5 to 7.5. The hydroxylation of methane and epoxidation of propene catalyzed by purified MMO were investigated. In addition, some metal ions can stimulate the MMO activity, implying that the MMO activity was closely related to metal ions. A variety of reducing agents were selected as electron donor but only NADPH could replace NADH.