7423-92-9Relevant articles and documents
Spectrophotometric Studies of the Copper(II)-D-o-Tyrosine Complex. Assignment of the 330-nm Dichroic Band in Copper(II) and Iron(III) Transferrins
Garnier-Suillerot, Arlette,Albertini, Jean-Paul,Collet, Andre,Faury, Liliane,Pastor, Jose-Maria,Tosi, Lucia
, p. 2544 - 2549 (1981)
The separation of both enantiomers of racemic o-tyrosine by means of binaphthylphosphoric acid has been undertaken.Copper(II) interacts with D-o-tyrosine to form two complexes.The first, obtained at pH 6, diplays a circular-dichroism (c.d.) spectral pattern characteristic of metal co-ordination through amino-nitrogens and carboxylate oxygens.The second complex starts to form at pH 8 and is fully defined at pH 10.5.Its c.d.spectrum, in the region below 400 nm, is very similar to those of iron(III) and copper(II) transferrins and displays two well defined bands at ca. 400 and 330 nm.So far, only the origin of the higher-frequency peak has been well established ar arising from a phenolate-oxygen-to-metal charge-transfer transition, whereas that of the lower-frequency peak remains uncertain.Resonance-Raman measurements upon excitation into the envelope of the two absorptions at 400 and 330 nm clearly indicate a common origin to both bands, namely: phenolate oxygen -> Cu(II) charge-transfer transition.
Kinetic of adsorption and of photocatalytic degradation of phenylalanine effect of pH and light intensity
Elsellami,Vocanson,Dappozze,Puzenat,Pa?sse,Houas,Guillard
experimental part, p. 142 - 148 (2011/10/12)
Phenylalanine (Phe) was chosen to study the TiO2 photocatalytic degradation of amino acids, which are at the origin of the formation of odorous compounds after chlorination. The photocatalytic degradation has been investigated in aqueous solutions containing TiO2 suspensions as photocatalyst, in order to assess the influence of various parameters, such as adsorption, initial concentration, pH and radiant flux on the photocatalytic process. Results showed no correlation between dark adsorption and photocatalytic degradation. A multilayer kinetic was observed in the dark with a monolayer corresponding to less that 1% of OH covered, whereas Langmuir-Hinshelwood model seems to modelize the photocatalytic disappearance of Phe. However, even if the form of the curve is similar to L-H model, the degradation of phenylalanine is not a kinetic of L-H as we could plan it by considering the adsorption of the phenylalanine in the dark. The study of the mineralization of carbon and nitrogen showed that nitrogen atoms were predominantly photoconverted into NH4+ and a total mineralization of nitrogen and carbon seems occur. The identification of the by-products by LC-MS reveal mono- and di-hydroxylation and nitrogen-carbon (N-C) cleavage. The effect of pH showed an increase of adsorption under acid pH but a decrease of disappearance rate. The more efficient degradation was found at basic pH. The evolution of hydroxylated compounds of phenylalanine as a function of conversion revealed the presence of more hydroxylated compounds at natural pH and at basic pH compared to acid pH suggesting a modification of mechanism with solution pH. The effect of the radiant flux evaluated under different initial concentration of phenylalanine allowed us to determine that Κ increases by increasing the radiant flux, whereas Κ decreases or remains constant from about a value of 3.5 mW/cm2. The disappearance rate as a function of radiant flux has been showed to reach a maximal value corresponding to a maximal quantum yield of 1.6%.
PROTEIN MODIFIER PRODUCTION INHIBITOR
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Page/Page column 19; 31-32, (2008/06/13)
[PLOBLEMS] To provide a inhibitor of protein modification products formation capable of inhibiting of vitamin B6 deficiency disease as a side effect, especially a renal protective agent. [MEANS FOR SOLVING PROBLEMS] There is provided a use, as an active ingredient, of any of free or salt-form compounds of either of the formulae: (I) (II) [wherein R1 is substituted or unsubstituted aromatic ring; and each of R2, R3 and R4 is a hydrogen atom or monovalent organic group, or alternatively R2 and R3 cooperate to form a condensed ring or R3 and R4 cooperate to represent a divalent organic group, provided that R3 and R4 are not simulataneously hydrogen atoms].
