tailieunhanh - Biomimetic Based Applications Part 11

Tham khảo tài liệu 'biomimetic based applications part 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Biomimetic Applications of Metal Systems Supported by Scorpionates 391 ligand L mimics the thioether-substituted Tyr272 of the enzyme Halcrow et al. 1998 Halcrow et al. 1999 . Fig. 5. Molecular structure of a HB pzCum-Me 3 Cu O MeS C6H4 b HB pzph 3 Cu L L 2-hydroxy-3-methylsulfanyl-5-methylbenzaldehyde c HB pzph-ph 3 Cu L HL 2-hydroxy-5-methyl-l 4-benzoquinone . Other HB pzph 3 Cun complexes containing chelate phenolates exhibit a similar arrangement around the copper center Halcrow et al. 1999 . HB pzph 3 Cu L was electrochemically oxidized to HB pzph 3 Cu L which is a good spectroscopic model of the diradical Cu II -phenoxo moiety of GOaseox being EPR silent and presenting comparable visible-NIR features Whittaker et al. 1996 . The electrochemical reversibility of the phenoxo phenoxy radical redox process not observed in the aforementioned HB pzCum-Me 3 Cu O MeS CóH4 model probably implies conservation of the square pyramidal geometry also in the oxidised form HB pzph 3 Cu L even though there is no structural evidence to support this hypothesis. Interestingly by introducing bulky substituents such as f-butyl group in the para position of the phenolic co-ligand a decrease in the kinetic stability of the electrochemically generated diradical Cu II -phenoxo species is observed Sylvestre et al. 2005 . The heteroscorpionate ligand 2-hydroxy-3-t-butyl-methylphenyl bis 3 5-dimethylpyrazolyl methane LIO gave the ternary complex Cu LlO OAc where the acetate ion is bound to the metal with both oxygen atoms. It has been proposed that the N3O donor set provided by LIO ligand serves as a mimic for two histine and the tyrosine residues Warthen Carrano 2003 . Copper amine oxidases CuAOases catalyze the aerobic oxidation of primary amines to aldehydes in some bacteria yeasts plants and mammals Klinman 1996 Mure et al. 2002 . The catalytic site contains a T2 copper center Cu His 3 OH2 n A n 0 or 2 and the organic cofactor 2- l-amino-l-carboxyethyl -5-hydroxy-l 4-benzoquinone TPQ