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Xu P, Pan C, Cui G, Wei C, Wang L, Li Y, Li X, Huang S. Enhancement of l-amino acid oxidase production by Bacillus subtilis HLZ-68 with oxygen-vector and asymmetric degradation of dl-arginine to d-arginine. BIOTECHNOL BIOTEC EQ 2020. [DOI: 10.1080/13102818.2020.1834454] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Affiliation(s)
- Peng Xu
- College of Life Science and Technology, Guangxi University, Nanning, China
| | - Changpei Pan
- Nanning Science and Technology Enterprise Incubation Base Co., Ltd., Nanning, China
| | - Gongcheng Cui
- College of Life Science and Technology, Guangxi University, Nanning, China
| | - ChunYan Wei
- College of Life Science and Technology, Guangxi University, Nanning, China
| | - Lijuan Wang
- College of Life Science and Technology, Guangxi University, Nanning, China
| | - Yanting Li
- College of Life Science and Technology, Guangxi University, Nanning, China
| | - Xiangping Li
- College of Animal Science and Technology, Guangxi University, Nanning, China
| | - Shihai Huang
- College of Life Science and Technology, Guangxi University, Nanning, China
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2
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Wu L, Guo X, Wu G, Liu P, Liu Z. Efficient production of α-keto acids by immobilized E. coli-pETduet-1- PmiLAAO in a jacketed packed-bed reactor. ROYAL SOCIETY OPEN SCIENCE 2019; 6:182035. [PMID: 31183133 PMCID: PMC6502377 DOI: 10.1098/rsos.182035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 03/01/2019] [Indexed: 06/09/2023]
Abstract
α-keto acids are compounds of primary interest for the fine chemical, pharmaceutical and agrochemical sectors. l-amino acid oxidases as an efficient tool are used for α-keto acids preparation in this study. Firstly, an l-amino acid oxidase (PmiLAAO) from Proteus mirabilis was discovered by data mining. Secondly, by gene expression vector screening, pETDuet-1-PmiLAAO activity improved by 130%, as compared to the pET20b-PmiLAAO. PmiLAAO production was increased to 9.8 U ml-1 by optimized expression condition (OD600 = 0.65, 0.45 mmol l-1 IPTG, 20 h of induction). Furthermore, The PmiLAAO was stabile in the pH range of 4.0-9.0 and in the temperature range of 10-40°C; the optimal pH and temperature of recombinant PmiLAAO were 6.5 and 37°C, respectively. Afterwards, in order to simplify product separation process, E. coli-pETduet-1-PmiLAAO was immobilized in Ca-alginate beads. Continuous production of 2-oxo-3-phenylpropanoic acid was conducted in a packed-bed reactor via immobilized E. coli-pETduet-1-PmiLAAO. Significantly, 29.66 g l-1 2-oxo-3-phenylpropanoic acid with a substrate conversion rate of 99.5% was achieved by correspondingly increasing the residence time (25 h). This method holds the potential to be used for efficiently producing pure α-keto acids.
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Affiliation(s)
- Licheng Wu
- Department of R&D of zhejiang zhengshuo Biological Co., Ltd, Huzhou 313000, Zhejiang, People's Republic of China
| | - Xiaolei Guo
- College of life science, Fujian normal university, Fuzhou, Fujian 350000, People's Republic of China
| | - Gaobing Wu
- College of Life Science and Technology, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
| | - Pengfu Liu
- Zhejiang University of Technology, Hangzhou 310014, Zhejiang, People's Republic of China
| | - Ziduo Liu
- College of Life Science and Technology, State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, People's Republic of China
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Campillo-Brocal JC, Lucas-Elío P, Sanchez-Amat A. Distribution in Different Organisms of Amino Acid Oxidases with FAD or a Quinone As Cofactor and Their Role as Antimicrobial Proteins in Marine Bacteria. Mar Drugs 2015; 13:7403-18. [PMID: 26694422 PMCID: PMC4699246 DOI: 10.3390/md13127073] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 11/27/2015] [Accepted: 12/08/2015] [Indexed: 12/27/2022] Open
Abstract
Amino acid oxidases (AAOs) catalyze the oxidative deamination of amino acids releasing ammonium and hydrogen peroxide. Several kinds of these enzymes have been reported. Depending on the amino acid isomer used as a substrate, it is possible to differentiate between l-amino acid oxidases and d-amino acid oxidases. Both use FAD as cofactor and oxidize the amino acid in the alpha position releasing the corresponding keto acid. Recently, a novel class of AAOs has been described that does not contain FAD as cofactor, but a quinone generated by post-translational modification of residues in the same protein. These proteins are named as LodA-like proteins, after the first member of this group described, LodA, a lysine epsilon oxidase synthesized by the marine bacterium Marinomonas mediterranea. In this review, a phylogenetic analysis of all the enzymes described with AAO activity has been performed. It is shown that it is possible to recognize different groups of these enzymes and those containing the quinone cofactor are clearly differentiated. In marine bacteria, particularly in the genus Pseudoalteromonas, most of the proteins described as antimicrobial because of their capacity to generate hydrogen peroxide belong to the group of LodA-like proteins.
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Affiliation(s)
- Jonatan C Campillo-Brocal
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain.
| | - Patricia Lucas-Elío
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain.
| | - Antonio Sanchez-Amat
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain.
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4
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D'Arrigo P, Allegretti C, Fiorati A, Piubelli L, Rosini E, Tessaro D, Valentino M, Pollegioni L. Immobilization of l-aspartate oxidase from Sulfolobus tokodaii as a biocatalyst for resolution of aspartate solutions. Catal Sci Technol 2015. [DOI: 10.1039/c4cy00968a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
l-Aspartate oxidase from the thermophilic archaebacterium Sulfolobus tokodaii (StLASPO) catalyzes the stereoselective oxidative deamination of l-aspartate to yield oxaloacetate, ammonia and hydrogen peroxide.
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Affiliation(s)
- Paola D'Arrigo
- Dipartimento di Chimica
- Materiali e Ingegneria Chimica “Giulio Natta”
- Politecnico di Milano
- 20133 Milano
- Italy
| | - Chiara Allegretti
- Dipartimento di Chimica
- Materiali e Ingegneria Chimica “Giulio Natta”
- Politecnico di Milano
- 20133 Milano
- Italy
| | - Andrea Fiorati
- Dipartimento di Chimica
- Materiali e Ingegneria Chimica “Giulio Natta”
- Politecnico di Milano
- 20133 Milano
- Italy
| | - Luciano Piubelli
- The Protein Factory
- Politecnico di Milano
- ICRM CNR Milano
- and Università degli Studi dell'Insubria
- 20131 Milano
| | - Elena Rosini
- The Protein Factory
- Politecnico di Milano
- ICRM CNR Milano
- and Università degli Studi dell'Insubria
- 20131 Milano
| | - Davide Tessaro
- Dipartimento di Chimica
- Materiali e Ingegneria Chimica “Giulio Natta”
- Politecnico di Milano
- 20133 Milano
- Italy
| | - Mattia Valentino
- The Protein Factory
- Politecnico di Milano
- ICRM CNR Milano
- and Università degli Studi dell'Insubria
- 20131 Milano
| | - Loredano Pollegioni
- The Protein Factory
- Politecnico di Milano
- ICRM CNR Milano
- and Università degli Studi dell'Insubria
- 20131 Milano
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5
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Advances in Detection Methods of l-Amino Acid Oxidase Activity. Appl Biochem Biotechnol 2014; 174:13-27. [DOI: 10.1007/s12010-014-1005-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 05/26/2014] [Indexed: 10/25/2022]
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6
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Pollegioni L, Motta P, Molla G. L-amino acid oxidase as biocatalyst: a dream too far? Appl Microbiol Biotechnol 2014; 97:9323-41. [PMID: 24077723 DOI: 10.1007/s00253-013-5230-1] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 08/29/2013] [Accepted: 09/02/2013] [Indexed: 12/27/2022]
Abstract
L-amino acid oxidase (LAAO) is a flavoenzyme containing non-covalently bound flavin adenine dinucleotide, which catalyzes the stereospecific oxidative deamination of l-amino acids to α-keto acids and also produces ammonia and hydrogen peroxide via an imino acid intermediate. LAAOs purified from snake venoms are the best-studied members of this family of enzymes, although a number of LAAOs from bacterial and fungal sources have been also reported. From a biochemical point of view, LAAOs from different sources are distinguished by molecular mass, substrate specificity, post-translational modifications and regulation. In analogy to the well-known biotechnological applications of d-amino acid oxidase, important results are expected from the availability of suitable LAAOs; however, these expectations have not been fulfilled yet because none of the "true" LAAOs has successfully been expressed as a recombinant protein in prokaryotic hosts, such as Escherichia coli. In enzyme biotechnology, recombinant production of a protein is mandatory both for the production of large amounts of the catalyst and to improve its biochemical properties by protein engineering. As an alternative, flavoenzymes active on specific l-amino acids have been identified, e.g., l-aspartate oxidase, l-lysine oxidase, l-phenylalanine oxidase, etc. According to presently available information, amino acid oxidases with "narrow" or "strict" substrate specificity represent as good candidates to obtain an enzyme more suitable for biotechnological applications by enlarging their substrate specificity by means of protein engineering.
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7
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Identification, cloning, and expression of L-amino acid oxidase from marine Pseudoalteromonas sp. B3. ScientificWorldJournal 2014; 2014:979858. [PMID: 24526926 PMCID: PMC3913195 DOI: 10.1155/2014/979858] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Accepted: 10/22/2013] [Indexed: 11/17/2022] Open
Abstract
L-amino acid oxidase (LAAO) is attracting more attentions due to its broad and important biological functions. Recently, an LAAO-producing marine microorganism (strain B3) was isolated from the intertidal zone of Dinghai sea area, China. Physiological, biochemical, and molecular identifications together with phylogenetic analysis congruously suggested that it belonged to the genus Pseudoalteromonas. Therefore, it was designated as Pseudoalteromonas sp. B3. Its capability of LAAO production was crossly confirmed by measuring the products of H2O2, a-keto acids, and NH4+ in oxidization reaction. Two rounds of PCR were performed to gain the entire B3-LAAO gene sequence of 1608 bps in length encoding for 535 amino acid residues. This deduced amino acid sequence showed 60 kDa of the calculated molecular mass, supporting the SDS-PAGE result. Like most of flavoproteins, B3-LAAO also contained two conserved typical motifs, GG-motif and βαβ-dinucleotide-binding domain motif. On the other hand, its unique substrate spectra and sequence information suggested that B3-LAAO was a novel LAAO. Our results revealed that it could be functionally expressed in E. coli BL21(DE3) using vectors, pET28b(+) and pET20b(+). However, compared with the native LAAO, the expression level of the recombinant one was relatively low, most probably due to the formation of inclusion bodies. Several solutions are currently being conducted in our lab to increase its expression level.
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Yu Z, Wang J, Zhou N, Zhao C, Qiu J. A highly sensitive method for quantitative determination of L-amino acid oxidase activity based on the visualization of ferric-xylenol orange formation. PLoS One 2013; 8:e82483. [PMID: 24376540 PMCID: PMC3869696 DOI: 10.1371/journal.pone.0082483] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 10/21/2013] [Indexed: 11/19/2022] Open
Abstract
L-amino acid oxidase (LAAO) has important biological roles in many organisms, thus attracting great attention from researchers to establish its detection methods. In this study, a new quantitative in-gel determination of LAAO activity based on ferric-xylenol orange (Fe(III)XO) formation was established. This method showed that due to the conversion of Fe(II) to Fe(III) by H2O2 and subsequent formation of Fe(III)XO complex halo in agar medium, the logarithm of H2O2 concentration from 5 to 160 µM was linearly correlated to the diameter of purplish red Fe(III)XO halo. By extracting the LAAO-generated H2O2 concentration, the LAAO activity can be quantitatively determined. This Fe(III)XO agar assay is highly sensitive to detect H2O2 down to micromolar range. More importantly, it is easy to handle, cheap, reproducible, convenient and accurate. Coupled with SDS-PAGE, it can directly be used to determine the number and approximate molecular weight of LAAO in one assay. All these features make this in-gel Fe(III)XO assay useful and convenient as a general procedure for following enzyme purification, assaying fractions from a column, or observing changes in activity resulting from enzyme modifications, hence endowing this method with broad applications.
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Affiliation(s)
- Zhiliang Yu
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, China
- * E-mail: (ZY); (JQ)
| | - Ju Wang
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, China
| | - Ning Zhou
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, China
| | - Chuntian Zhao
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, China
| | - Juanping Qiu
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, China
- * E-mail: (ZY); (JQ)
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9
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L-Amino acid oxidases from microbial sources: types, properties, functions, and applications. Appl Microbiol Biotechnol 2013; 98:1507-15. [PMID: 24352734 DOI: 10.1007/s00253-013-5444-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 11/26/2013] [Accepted: 11/27/2013] [Indexed: 10/25/2022]
Abstract
L-Amino acid oxidases (LAAOs), which catalyze the stereospecific oxidative deamination of L-amino acids to α-keto acids and ammonia, are flavin adenine dinucleotide-containing homodimeric proteins. L-Amino acid oxidases are widely distributed in diverse organisms and have a range of properties. Because expressing LAAOs as recombinant proteins in heterologous hosts is difficult, their biotechnological applications have not been thoroughly advanced. LAAOs are thought to contribute to amino acid catabolism, enhance iron acquisition, display antimicrobial activity, and catalyze keto acid production, among other roles. Here, we review the types, properties, structures, biological functions, heterologous expression, and applications of LAAOs obtained from microbial sources. We expect this review to increase interest in LAAO studies.
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10
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In-gel determination of L-amino acid oxidase activity based on the visualization of Prussian blue-forming reaction. PLoS One 2013; 8:e55548. [PMID: 23383337 PMCID: PMC3562322 DOI: 10.1371/journal.pone.0055548] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 01/02/2013] [Indexed: 11/19/2022] Open
Abstract
L-amino acid oxidase (LAAO) is attracting increasing attention due to its important functions. Diverse detection methods with their own properties have been developed for characterization of LAAO. In the present study, a simple, rapid, sensitive, cost-effective and reproducible method for quantitative in-gel determination of LAAO activity based on the visualization of Prussian blue-forming reaction is described. Coupled with SDS-PAGE, this Prussian blue agar assay can be directly used to determine the numbers and approximate molecular weights of LAAO in one step, allowing straightforward application for purification and sequence identification of LAAO from diverse samples.
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11
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Arinbasarova AY, Ashin VV, Makrushin KV, Medentsev AG, Lukasheva EV, Berezov TT. Isolation and properties of L-lysine-α-oxidase from the fungus Trichoderma cf. aureoviride RIFAI VKM F-4268D. Microbiology (Reading) 2012. [DOI: 10.1134/s0026261712050037] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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12
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Yu Z, Qiao H. Advances in non-snake venom L-amino acid oxidase. Appl Biochem Biotechnol 2012; 167:1-13. [PMID: 22367642 DOI: 10.1007/s12010-012-9611-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Accepted: 02/10/2012] [Indexed: 11/28/2022]
Abstract
L-amino acid oxidase is widely found in diverse organisms and has different properties. It is thought to contribute to antimicrobial activity, amino acid catabolism, and so forth. The purpose of this communication is to summarize the advances in non-snake venom L-amino acid oxidase, including its enzymatic and structural properties, gene cloning and expression, and biological function. In addition, the mechanism of its biological function as well as its application is also discussed.
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Affiliation(s)
- Zhiliang Yu
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, China.
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13
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Lukasheva E, Efremova A, Treshalina E, Arinbasarova A, Medentzev A, Berezov T. L-amino acid oxidases: properties and molecular mechanisms of action. ACTA ACUST UNITED AC 2012; 58:372-84. [DOI: 10.18097/pbmc20125804372] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
During previous decade L-amino acid oxidases (LAAO) attracted the steady interest of researchers due to their poly functional effects on different biological systems. The review summarizes information concerning the sources, structure, phisico-chemical and catalytical properties of LAAO which exhibit antibacterial, antifungal, antiprotozoal, antiviral effects as well as the ambiguous action on platelet aggregation. Special attention is devoted to the elucidation of molecular mechanisms of LAAO action. It is proposed that the unique properties of LAAO are based on their catalytic reaction, which causes the decrease of L-amino acid levels, including the essential amino acids and formation of hydrogen peroxide. The action of liberated H2O2 on cells involves the synthesis of oxygen reactive species and the development of necrotic and apoptotic pathways of cell death. The presence of carbohydrate moieties in LAAO molecules promotes their attachment to cell's surface and creation of high H2O2 local concentrations. The wide range of LAAO biological effects is undoubtedly connected with their important functional roles in the organism. In particular, it was shown that in the mice brain the LAAO-catalyzed reaction is the single pathway of L-lysine degradation, while in the mice milk LAAO carry out the antibacterial effect and in human leucocytes LAAO take part in fulfilling their defending role. Protector action may be also attributed to the oxidases from the other numerous sources: microscopic fungi, snake venoms and sea inhabitants.
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Affiliation(s)
- E.V. Lukasheva
- Department of Biochemistry, Medical Faculty, Russian Peoples’ Friendship University
| | - A.A. Efremova
- Department of Biochemistry, Medical Faculty, Russian Peoples’ Friendship University
| | - E.M. Treshalina
- N. N. Blokhin Cancer Research Center,Russian Academy of Medical Sciences
| | - A.Ju. Arinbasarova
- G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences
| | - A.G. Medentzev
- G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences
| | - T.T. Berezov
- Department of Biochemistry, Medical Faculty, Russian Peoples’ Friendship University
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Lukasheva EV, Efremova AA, Treshalina EM, Arinbasarova AY, Medentzev AG, Berezov TT. L-Amino acid oxidases: Properties and molecular mechanisms of action. BIOCHEMISTRY MOSCOW-SUPPLEMENT SERIES B-BIOMEDICAL CHEMISTRY 2011. [DOI: 10.1134/s199075081104007x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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15
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Singh S, Gogoi BK, Bezbaruah RL. Racemic resolution of some DL-amino acids using Aspergillus fumigatus L-amino acid oxidase. Curr Microbiol 2011; 63:94-9. [PMID: 21590326 DOI: 10.1007/s00284-011-9955-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 05/05/2011] [Indexed: 11/25/2022]
Abstract
The ability of Aspergillus fumigatus L-amino acid oxidase (L-aao) to cause the resolution of racemic mixtures of DL-amino acids was investigated with DL-alanine, DL-phenylalanine, DL-tyrosine, and DL-aspartic acid. A chiral column, Crownpak CR+ was used for the analysis of the amino acids. The enzyme was able to cause the resolution of the three DL-amino acids resulting in the production of optically pure D-alanine (100% resolution), D-phenylalanine (80.2%), and D-tyrosine (84.1%), respectively. The optically pure D-amino acids have many uses and thus can be exploited industrially. This is the first report of the use of A. fumigatus L: -amino acid oxidase for racemic resolution of DL-amino acids.
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Affiliation(s)
- Susmita Singh
- Biotechnology Division, North East Institute of Science and Technology, Council of Scientific and Industrial Research, Jorhat, 785006, Assam, India.
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Sanchez-Amat A, Solano F, Lucas-Elío P. Finding new enzymes from bacterial physiology: a successful approach illustrated by the detection of novel oxidases in Marinomonas mediterranea. Mar Drugs 2010; 8:519-41. [PMID: 20411113 PMCID: PMC2855505 DOI: 10.3390/md8030519] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 02/21/2010] [Accepted: 02/22/2010] [Indexed: 12/04/2022] Open
Abstract
The identification and study of marine microorganisms with unique physiological traits can be a very powerful tool discovering novel enzymes of possible biotechnological interest. This approach can complement the enormous amount of data concerning gene diversity in marine environments offered by metagenomic analysis, and can help to place the activities associated with those sequences in the context of microbial cellular metabolism and physiology. Accordingly, the detection and isolation of microorganisms that may be a good source of enzymes is of great importance. Marinomonas mediterranea, for example, has proven to be one such useful microorganism. This Gram-negative marine bacterium was first selected because of the unusually high amounts of melanins synthesized in media containing the amino acid L-tyrosine. The study of its molecular biology has allowed the cloning of several genes encoding oxidases of biotechnological interest, particularly in white and red biotechnology. Characterization of the operon encoding the tyrosinase responsible for melanin synthesis revealed that a second gene in that operon encodes a protein, PpoB2, which is involved in copper transfer to tyrosinase. This finding made PpoB2 the first protein in the COG5486 group to which a physiological role has been assigned. Another enzyme of interest described in M. mediterranea is a multicopper oxidase encoding a membrane-associated enzyme that shows oxidative activity on a wide range of substrates typical of both laccases and tyrosinases. Finally, an enzyme very specific for L-lysine, which oxidises this amino acid in epsilon position and that has received a new EC number (1.4.3.20), has also been described for M. mediterranea. Overall, the studies carried out on this bacterium illustrate the power of exploring the physiology of selected microorganisms to discover novel enzymes of biotechnological relevance.
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Affiliation(s)
- Antonio Sanchez-Amat
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, Campus de Espinardo, Murcia 30100, Spain; E-Mail:
| | - Francisco Solano
- Department of Biochemistry and Molecular Biology B and Immunology, School of Medicine, University of Murcia, Murcia 30100, Spain; E-Mail:
| | - Patricia Lucas-Elío
- Department of Genetics and Microbiology, Faculty of Biology, University of Murcia, Campus de Espinardo, Murcia 30100, Spain; E-Mail:
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