A5078744295- melanin and skin pigmentation
- Protein Structure and Dynamics
- Biochemical Analysis and Sensing Techniques
- Enzyme Catalysis and Immobilization
- Monoclonal and Polyclonal Antibodies Research
- Phytochemicals and Antioxidant Activities
- Free Radicals and Antioxidants
- Microbial Metabolic Engineering and Bioproduction
- Hemoglobin structure and function
- Computational Drug Discovery Methods
- Postharvest Quality and Shelf Life Management
- Protein Interaction Studies and Fluorescence Analysis
- Biochemical and biochemical processes
- thermodynamics and calorimetric analyses
- Molecular Junctions and Nanostructures
- Mass Spectrometry Techniques and Applications
- Protein purification and stability
- Gene Regulatory Network Analysis
- Receptor Mechanisms and Signaling
- Plant Physiology and Cultivation Studies
- Chemical Reaction Mechanisms
- Analytical Chemistry and Chromatography
- Biochemical and Molecular Research
- Enzyme-mediated dye degradation
- Fermentation and Sensory Analysis
University of Castilla-La Mancha
2007-2016
Universidad de Murcia
1981-2007
Kiel University
1990-1998
2,3-dihydro-5,6-dihydroxyindole-2-carboxylate; tyrosine, L-tyrosine; dopa, ~-3,4-dihydroxyphenyIalanine; o-dopaquinone, 4-(2-carboxy-2aminoethyl)-1,2-benzoquinone; dopachrome, 2-carboxy-2,3-dihydroindole-5,6
This paper reports a quantitative study of the effect ring substituents in 1‐position aromatic on rate monophenol hydroxylation and o ‐diphenol oxidation catalyzed by tyrosinase. A possible correlation between electron density carbon atom supporting oxygen from monophenolic hydroxyl group V M max values for each was found. In case ‐diphenols same observed but size side‐chain became very important. NMR studies monophenols justified sequence obtained. As regards ‐diphenols, other hand, only...
The reaction of mushroom (Agaricus bisporus) tyrosinase with dioxygen in the presence several o-diphenolic substrates has been studied by steady-state and transient-phase kinetics order to elucidate rate-limiting step provide new insights into mechanism oxidation these substrates. A kinetic analysis allowed for first time determination individual rate constants partial reactions that comprise catalytic cycle. Mushroom rapidly reacts a second-order constant k(+8) = 2.3 x 10(7) M(-)(1)...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTime-dependent inhibition of grape polyphenol oxidase by tropoloneEdelmira Valero, Manuela Garcia-Moreno, Ramon Varon, and Francisco Garcia-CarmonaCite this: J. Agric. Food Chem. 1991, 39, 6, 1043–1046Publication Date (Print):June 1, 1991Publication History Published online1 May 2002Published inissue 1 June 1991https://pubs.acs.org/doi/10.1021/jf00006a007https://doi.org/10.1021/jf00006a007research-articleACS PublicationsRequest reuse...
ABSTRACT Polyphenol oxidase (PPO) was isolated from grapes grown in Spain and its characteristics were studied. The partially purified enzyme had both cresolase catecholase activities. Catecholase activity a pH optimum range 3.5–4.5 characterized by relatively high stability to heat. apparent K M for 4‐methylcatechol 9.5 mM. Cresolase presents lag period which is modulated different factors: concentration, substrate temperature or pH. presence of o‐diphenols the reaction medium abolishes...
This paper reports a quantitative study of the effect ring substituents on rate monophenol hydroxylation and o-diphenol oxidation catalyzed by apple pear polyphenol oxidases. A good correlation between electronic density at carbon atom in 4-position aromatic for each Vmax values was found. However, this not so 3- 4-positions o- diphenols assayed. NMR studies monophenols demonstrated higher reactivity 4-hydroxyanisole compared with other Catechol best o-diphenolic substrate assayed because...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMonophenolase activity of polyphenol oxidase from Verdedoncella appleJuan Carlos Espin, Mercedes Morales, Ramon Varon, Jose Tudela, and Francisco Garcia-CanovasCite this: J. Agric. Food Chem. 1995, 43, 11, 2807–2812Publication Date (Print):November 1, 1995Publication History Published online1 May 2002Published inissue 1 November 1995https://pubs.acs.org/doi/10.1021/jf00059a007https://doi.org/10.1021/jf00059a007research-articleACS...
The Michaelis constant of tyrosinase for oxygen in the presence monophenols and o-diphenols, which generate a cyclizable o-quinone, has been studied. This depends on nature monophenol o-diphenol is always lower former than latter. From mechanism proposed from its kinetic analysis [Rodríguez-López, J. N., Tudela, J., Varón, R., García-Carmona, F. García-Cánovas, (1992) Biol. Chem. 267, 3801-3810] quantitative ratio established between constants their o-diphenols. used determination with when...
ABSTRACT The coloring power and bitterness of ground saffron stored at 40°C with relative air humidity 75% were investigated. loss color followed first order kinetics the second kinetics.