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Manzano-Nicolas J, Taboada-Rodriguez A, Teruel-Puche JA, Marin-Iniesta F, Garcia-Molina F, Garcia-Canovas F, Tudela-Serrano J, Muñoz-Muñoz JL. Kinetic characterization of the oxidation of catecolamines and related compounds by laccase. Int J Biol Macromol 2020; 164:1256-1266. [DOI: 10.1016/j.ijbiomac.2020.07.112] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 07/10/2020] [Accepted: 07/10/2020] [Indexed: 11/28/2022]
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Eslami M, Zare HR, Namazian M. The effect of solvents on the electrochemical behavior of homogentisic acid. J Electroanal Chem (Lausanne) 2014. [DOI: 10.1016/j.jelechem.2014.03.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Chatterjee S, Prados-Rosales R, Frases S, Itin B, Casadevall A, Stark RE. Using solid-state NMR to monitor the molecular consequences of Cryptococcus neoformans melanization with different catecholamine precursors. Biochemistry 2012; 51:6080-8. [PMID: 22765382 PMCID: PMC3448835 DOI: 10.1021/bi300325m] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Melanins are a class of natural pigments associated with a wide range of biological functions, including microbial virulence, energy transduction, and protection against solar radiation. Because of their insolubility and structural heterogeneity, solid-state nuclear magnetic resonance (NMR) spectroscopy provides an unprecedented means to define the molecular architecture of these enigmatic pigments. The requirement of obligatory catecholamines for melanization of the pathogenic fungus Cryptococcus neoformans also offers unique opportunities for investigating melanin development. In the current study, pigments produced with L-dopa, methyl-L-dopa, epinephrine, and norepinephrine precursors are compared structurally using (13)C and (1)H magic-angle spinning (MAS) NMR. Striking structural differences were observed for both aromatic and aliphatic molecular constituents of the mature fungal pigment assemblies, thus making it possible to redefine the molecular prerequisites for formation of the aromatic domains of insoluble indole-based biopolymers, to rationalize their distinctive physical characteristics, and to delineate the role of cellular constituents in assembly of the melanized macromolecules with polysaccharides and fatty acyl chain-containing moieties. By achieving an augmented understanding of the mechanisms of C. neoformans melanin biosynthesis and cellular assembly, such studies can guide future drug discovery efforts related to melanin-associated virulence, resistance to tumor therapy, and production of melanin mimetics under cell-free conditions.
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Affiliation(s)
- Subhasish Chatterjee
- Department of Chemistry, City College of New York, Graduate Center and Institute for Macromolecular Assemblies, City University of New York, New York, NY 10031, USA
| | - Rafael Prados-Rosales
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Yeshiva University, Bronx, New York 10461, USA
| | - Susana Frases
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Yeshiva University, Bronx, New York 10461, USA
| | - Boris Itin
- New York Structural Biology Center, New York, NY 10027
| | - Arturo Casadevall
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Yeshiva University, Bronx, New York 10461, USA
| | - Ruth E. Stark
- Department of Chemistry, City College of New York, Graduate Center and Institute for Macromolecular Assemblies, City University of New York, New York, NY 10031, USA
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Rembischevski P, Gemal AL. DETERMINATION OF THE INFLUENCE OF BORATE ION ON THE DEGRADATION OF L-α-METHYLDOPA USING RP-HPLC WITH PHOTODIODE ARRAY DETECTION. J LIQ CHROMATOGR R T 2007. [DOI: 10.1081/jlc-100106093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Peter Rembischevski
- a Instituto de Tecnologia em Fármacos , Fundação Oswaldo Cruz, Sizenando Nabuco 100-Manguinhos, Rio de Janeiro, 21041-250, Brazil
| | - André L. Gemal
- b Instituto de Química, Universidade Federal do Rio de Janeiro, Cidade Universitária , CT-Bloco A, Rio de Janeiro, 21949-900, Brazil
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Fenoll LG, Peñalver MJ, Rodríguez-López JN, Varón R, García-Cánovas F, Tudela J. Tyrosinase kinetics: discrimination between two models to explain the oxidation mechanism of monophenol and diphenol substrates. Int J Biochem Cell Biol 2004; 36:235-46. [PMID: 14643889 DOI: 10.1016/s1357-2725(03)00234-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The kinetic behaviour of tyrosinase is very complex because the enzymatic oxidation of monophenol and o-diphenol to o-quinones occurs simultaneously with the coupled non-enzymatic reactions of the latter. Both reaction types are included in the kinetic mechanism proposed for tyrosinase (Mechanism I [J. Biol. Chem. 267 (1992) 3801-3810]). We previously confirmed the validity of the rate equations by the oxidation of numerous monophenols and o-diphenols catalysed by tyrosinase from different fruits and vegetables. Other authors have proposed a simplified reaction mechanism for tyrosinase (Mechanism II [Theor. Biol. 203 (2000) 1-12]), although without deducing the rate equations. In this paper, we report new experimental work that provides the lag period value, the steady-state rate, o-diphenol concentration released to the reaction medium. The contrast between these experimental data and the respective numerical simulations of both mechanisms demonstrates the feasibility of Mechanism I. The need for the steps omitted from Mechanism II to interpret the experimental data for tyrosinase, based on the rate equations previously deduced for Mechanism I is explained.
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Affiliation(s)
- L G Fenoll
- GENZ-Grupo de Investigación Enzimologi;a, Departamento de Bioquímica y Biología Molecular-A, Facultad de Biología, Universidad de Murcia, A. Correos 4021 E-30080, Murcia, Spain
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Fenoll LG, Rodríguez-López JN, García-Molina F, García-Cánovas F, Tudela J. Michaelis constants of mushroom tyrosinase with respect to oxygen in the presence of monophenols and diphenols. Int J Biochem Cell Biol 2002; 34:332-6. [PMID: 11854032 DOI: 10.1016/s1357-2725(01)00133-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The complex reaction mechanism of tyrosinase involves three enzymatic forms, two overlapping catalytic cycles and a dead-end complex. Analytical expressions for the catalytic and Michaelis constants of tyrosinase towards phenols and oxygen were derived for both, monophenolase and diphenolase activities of the enzyme. Thus, the Michaelis constants of tyrosinase towards the oxygen (K(mO(2))) are related with the respective catalytic constants for monphenols (k(M)(cat)) and o-diphenols (k(D)(cat)), as well as with the rate constant, k(+8). We recently determined the experimental value of the rate constant for the binding of oxygen to deoxytyrosinase (k(+8)) by stopped-flow assays. In this paper, we calculate theoretical values of K(mO(2)) from the experimental values of catalytic constants and k(+8) towards several monophenols and o-diphenols. The reliability and the significance of the values of K(mO(2)) are discussed.
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Affiliation(s)
- Lorena G Fenoll
- GENZ: Grupo de Investigación Enzimología, Departamento de Bioquímica y Biología Molecular-A, Facultad de Biología, A. Correos 4201 Universidad de Murcia, Espinardo, E-30080 Murcia, Spain
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Fenoll LG, Rodríguez-López JN, García-Sevilla F, García-Ruiz PA, Varón R, García-Cánovas F, Tudela J. Analysis and interpretation of the action mechanism of mushroom tyrosinase on monophenols and diphenols generating highly unstable o-quinones. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1548:1-22. [PMID: 11451433 DOI: 10.1016/s0167-4838(01)00207-2] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Tyrosinase can act on monophenols because of the mixture of met- (E(m)) and oxy-tyrosinase (E(ox)) which exists in the native form of the enzyme. The latter form is active on monophenols, while the former is not. However, the kinetics are complicated because monophenols can bind to both enzyme forms. This situation becomes even more complex since the products of the enzymatic reaction, the o-quinones, are unstable and continue evolving to generate o-diphenols in the medium. In the case of substrates such as L-tyrosine, tyrosinase generates very unstable o-quinones, in which a process of cyclation and subsequent oxidation-reduction generates o-diphenol through non-enzymatic reactions. However, the release of o-diphenol through the action of the enzyme on the monophenol contributes to the concentration of o-diphenol in the first pseudo-steady-state [D(0)](ss). Hence, the system reaches an initial pseudo-steady state when t-->0 and undergoes a transition phase (lag period) until a final steady state is reached when the concentration of o-diphenol in the medium reaches the concentration of the final steady state [D(f)](ss). These results can be explained by taking into account the kinetic and structural mechanism of the enzyme. In this, tyrosinase hydroxylates the monophenols to o-diphenols, generating an intermediate, E(m)D, which may oxidise the o-diphenol or release it directly to the medium. We surmise that the intermediate generated during the action of E(ox) on monophenols, E(m)D, has axial and equatorial bonds between the o-diphenol and copper atoms of the active site. Since the orbitals are not coplanar, the concerted oxidation-reduction reaction cannot occur. Instead, a bond, probably that of C-4, is broken to achieve coplanarity, producing a more labile intermediate that will then release the o-diphenol to the medium or reunite it diaxially, involving oxidation to o-quinone. The non-enzymatic evolution of the o-quinone would generate the o-diphenol ([D(f)](ss)) necessary for the final steady state to be reached after the lag period.
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Affiliation(s)
- L G Fenoll
- GENZ: Grupo de Investigación Enzimologia, Departmento de Bioquímica y Biologia Molecular-A, Facultad de Biologia, Universidad de Murcia, Spain
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Fenoll LG, Rodríguez-López JN, García-Sevilla F, Tudela J, García-Ruiz PA, Varón R, García-Cánovas F. Oxidation by mushroom tyrosinase of monophenols generating slightly unstable o-quinones. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:5865-78. [PMID: 10998046 DOI: 10.1046/j.1432-1327.2000.01572.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Tyrosinase can act on monophenols because of the mixture of mettyrosinase (Em) and oxytyrosinase (Eox) that exists in the native form of the enzyme. The latter form is active on monophenols although the former is not. However, the kinetics are complicated because monophenols can bind to both enzyme forms. This situation becomes even more complex as the products of the enzymatic reaction, the o-quinones, are unstable and continue evolving to generate o-diphenols in the medium. In the case of substrates such as 4-methoxyphenol, 4-ethoxyphenol and 4-tert-butylphenol, tyrosinase generates o-quinones which become unstable with small constants of approximately < 10-3 s-1. The system evolves from an initial steady state, reached when t-->0, through a transition state towards a final steady state, which is never reached because the substrate is largely consumed. The mechanisms proposed to explain the enzyme's action can be differentiated by the kinetics of the first steady state. The results suggest that tyrosinase hydroxylates monophenols to o-diphenols, generating an intermediate Em-diphenol in the process, which may oxidize the o-diphenol or release it directly into the medium. In the case of o-quinone formation, its slow instability generates o-diphenol which activates the enzymatic system yielding parabolic time recordings.
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Affiliation(s)
- L G Fenoll
- GENZ:Grupo de Investigación Enzimología, Departamento de Bioquímica y Biología Molecular-A, Facultad de Biología, Universidad de Murcia, Murcia, Spain
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Affiliation(s)
- Alexander E. Shilov
- N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117977 Moscow, Russia
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