- PROTEIN MODIFIER PRODUCTION INHIBITOR
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[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].
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Page/Page column 19; 31-32
(2008/06/13)
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- Synthesis of chirally pure 2,5-disubstituted diketopiperazines derived from trisubstituted phenylalanines
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Some new chirally pure 2,5-substituted diketopiperazines were synthesized starting from 2-methoxybenzyl alcohol. This multistep synthesis proceeds through the enzymatic synthesis of chirally pure amino acids, protection and dipeptide coupling, cyclization of dipeptide ester formates, and nitration of the resulting diketopiperazines.
- Danthi, Satyavijayan Narasimhan,Hill, Ronald A.
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p. 835 - 844
(2007/10/03)
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- HYDROXYLATION OF AROMATIC RINGS IN AN AQUEOUS SOLUTION INDUCED BY ARGON ARC PLASMA
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Plasma-induced reaction in an aqueous solution of phenyl-containing amino acids resulted in the formation of several hydroxyphenyl amino acids, which was explained by the action of hydroxyl radicals generated by decomposition of water molecules by the high energy plasma.
- Takasaki, Michiaki,Harada, Kaoru
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p. 885 - 888
(2007/10/02)
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- Studies on the Hydroxylation of Phenylalanine by 6,7-Dimethyl-5,6,7,8-tetrahydropteridine
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The hydroxylation of phenylalanine by 6,7-dimethyl-5,6,7,8-tetrahydropteridine (DMPH4) was investigated.When phenylalanine was treated with DMPH4 in citrate buffer (pH 6.0), p-tyrosine, m-tyrosine and o-tyrosine were identified as hydroxylated products.The hydroxylation was pH-dependent, and the maximum rate was found at around pH 6.Replacement of air with nitrogen gas and the addition of hydroxyl radical scavengers or catalase prevented the hydroxylation.In contrast, ferrous ions significantly accelerated the hydroxylation as compared with other transition metal ions.In an aqueous solution of DMPH4 under aerobic conditions, the electron spin resonance (ESR) spectra of the hydroxyl radical spin adducts with spin traps such as α-phenyl N-tert-butylnitrone (PBN) and α-4-pyridyl 1-oxide N-tert-butyl nitrone (4-POBN) were observed.The results indicate that the hydroxylating effect of DMPH4 is caused by hydroxyl radicals formed during the autooxidation of DMPH4.Keywords - hydroxylation; phenylalanine; p-tyrosine; m-tyrosine; o-tyrosine; 6,7-dimethyl-5,6,7,8-tetrahydropteridine; ESR; spin-trapping; hydroxyl radical
- Ishimitsu, Susumu,Fujimoto, Sadaki,Ohara, Akira
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p. 752 - 756
(2007/10/02)
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