- Models for biological trinuclear copper clusters. Characterization and enantioselective catalytic oxidation of catechols by the copper(II) complexes of a chiral ligand derived from (S)-(-)-1,1'-binaphthyl-2,2'-diamine.
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The dinuclear and trinuclear Cu(II) complexes of an octadentate ligand derived from (S)-1,1'-binaphthyl-2,2'-diamine have been prepared and characterized by UV/Vis, CD, EPR and NMR spectroscopy. The ligand contains two tridentate aminobis(benzimidazole) d
- Mimmi, Maria Chiara,Gullotti, Michele,Santagostini, Laura,Battaini, Giuseppe,Monzani, Enrico,Pagliarin, Roberto,Zoppellaro, Giorgio,Casella, Luigi
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Read Online
- Mimicking hemoproteins: A new synthetic metalloenzyme based on a Fe(III)-mesoporphyrin functionalized by two helical decapeptides
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A new metalloenzyme formed by a Fe(III)-mesoporphyrin IX functionalized by two helical decapeptides was synthesized to mimic function and structural features of a hemoprotein active site. Each decapeptide comprises six 2-aminoisobutyric acid residues, whi
- Venanzi, Mariano,Cianfanelli, Sabrina,Palleschi, Antonio
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- Tyrosinase inactivation in its action on dopa
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Under aerobic or anaerobic conditions, tyrosinase undergoes a process of irreversible inactivation induced by its physiological substrate l-dopa. Under aerobic conditions, this inactivation occurs through a process of suicide inactivation involving the fo
- Mu?oz-Mu?oz,Acosta-Motos,Garcia-Molina,Varon,Garcia-Ruíz,Tudela,Garcia-Cánovas,Rodríguez-López
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experimental part
p. 1467 - 1475
(2011/12/01)
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- Stereospecificity of mushroom tyrosinase immobilized on a chiral and a nonchiral support
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Mushroom tyrosinase was immobilized from an extract onto glass beads covered with the cross-linked totally cinnamoylated derivates of D-sorbitol (sorbitol cinnamate) and glycerine (glycerine cinnamate). The enzyme was immobilized onto the support by direct adsorption, and the quantity of immobilized tyrosinase was higher for sorbitol cinnamate, the support with the higher number of esterified hydroxyls per unit of monosacharide, than for glycerine cinnamate. The results obtained from the stereospecificity study of the monophenolase and diphenolase activity of immobilized mushroom tyrosinase are reported. The enantiomers L-tyrosine, DL-tyrosine, D-tyrosine, L-dopa, DL-dopa, D-dopa, L-α-methyldopa, DL-α-methyldopa, L-isoprenaline, DL-isoprenaline, L-adrenaline, DL-adrenaline, L-noradrenaline, and D-noradrenaline were assayed with tyrosinase immobilized on a chiral support (sorbitol cinnamate), whereas L-tyrosine, DL-tyrosine, D-tyrosine, L-dopa, DL-dopa, D-dopa, L-α-methyldopa, and DL-α-methyldopa were assayed with tyrosinase immobilized on a nonchiral support (glycerine cinnamate). The same Vmaxapp values for each series of enantiomers were obtained. However, the Kmapp values were different, the L isomers showing lower values than the DL isomers, whereas the highest K mapp value was obtained with D isomers. No difference was observed in the stereospecificity of tyrosinase immobilized on a chiral (sorbitol cinnamate) or nonchiral (glycerine cinnamate) support.
- Marin-Zamora, Maria Elisa,Rojas-Melgarejo, Francisco,Garcia-Canovas, Francisco,Garcia-Ruiz, Pedro Antonio
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p. 4569 - 4575
(2008/02/09)
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- Metallo-ROS in Alzheimer's disease: Oxidation of neurotransmitters by CuII-β-amyloid and neuropathology of the disease
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A clear mind: The CuII-β-amyloid (Aβ) complex has been shown to exhibit enzyme-like metal-centered oxidative and hydroxylation catalyses. Metal-centered oxidation of various neurotransmitters by CuAβ under biomimetic conditions has verified the bio-relevance of the metal-centered catalyses and is expected to provide a chemical basis for the better understanding of the etiology of Alzheimer's disease. ROS = reactive oxygen species. (Figure Presented).
- Da Silva, Giordano F. Z.,Ming, Li-June
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p. 3337 - 3341
(2008/03/12)
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- Selective inhibition of Src protein tyrosine kinase by analogues of 5- S-glutathionyl-β-alanyl-L-dopa
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Twelve analogues of the antibacterial phenolic peptide 5-S- glutathionyl-β-alanyl-L-dopa (5-S-GA-L-D: 1) were synthesized via orthoquinones using tyrosinase. Several synthesized compounds inhibited the v-Src autophosphorylation tyrosine kinase reaction with an IC50 value comparable to that of herbimycin. The inhibition of c-Src substrate phosphorylation was much less active than v-Src autophosphorylation inhibition. The analogues showed no effects on substrate phosphorylation by epidermal growth factor receptor (EGFR), and this selectivity is the most characteristic feature of the analogues (1-12).
- Zheng, Zhe-Bin,Nagai, Sachie,Iwanami, Naoko,Kobayashi, Ayako,Hijikata, Mariko,Natori, Shunji,Sankawa, Ushio
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p. 1950 - 1951
(2007/10/03)
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