775-06-4Relevant articles and documents
Oxidative cyclization of N-methyl-dopa by a fungal flavoenzyme of the amine oxidase family
Lahham, Majd,Pavkov-Keller, Tea,Fuchs, Michael,Niederhauser, Johannes,Chalhoub, Gabriel,Daniel, Bastian,Kroutil, Wolfgang,Gruber, Karl,Macheroux, Peter
, p. 17021 - 17032 (2018/11/21)
Flavin-dependent enzymes catalyze many oxidations, including formation of ring structures in natural products. The gene cluster for biosynthesis of fumisoquins, secondary metabolites structurally related to isoquinolines, in the filamentous fungus Aspergillus fumigatus harbors a gene that encodes a flavoprotein of the amine oxidase family, termed fsqB (fumisoquin biosynthesis gene B). This enzyme catalyzes an oxidative ring closure reaction that leads to the formation of isoquinoline products. This reaction is reminiscent of the oxidative cyclization reported for berberine bridge enzyme and tetrahydrocannabinol synthase. Despite these similarities, amine oxidases and berberine bridge enzyme–like enzymes possess distinct structural properties, prompting us to investigate the structure–function relationships of FsqB. Here, we report the recombinant production and purification of FsqB, elucidation of its crystal structure, and kinetic analysis employing five putative substrates. The crystal structure at 2.6 ? resolution revealed that FsqB is a member of the amine oxidase family with a covalently bound FAD cofactor. N-methyl-dopa was the best substrate for FsqB and was completely converted to the cyclic isoquinoline product. The absence of the meta-hydroxyl group, as e.g. in L-Nmethyl-tyrosine, resulted in a 25-fold lower rate of reduction and the formation of the demethylated product L-tyrosine, instead of a cyclic product. Surprisingly, FsqB did not accept the D-stereoisomer of N-methyltyrosine, in contrast to N-methyl-dopa, for which both stereoisomers were oxidized with similar rates. On the basis of the crystal structure and docking calculations, we postulate a substrate-dependent population of distinct binding modes that rationalizes stereospecific oxidation in the FsqB active site.
Phenylalanine ammonia lyase catalyzed synthesis of amino acids by an MIO-cofactor independent pathway
Lovelock, Sarah L.,Lloyd, Richard C.,Turner, Nicholas J.
supporting information, p. 4652 - 4656 (2014/05/20)
Phenylalanine ammonia lyases (PALs) belong to a family of 4-methylideneimidazole-5-one (MIO) cofactor dependent enzymes which are responsible for the conversion of L-phenylalanine into trans-cinnamic acid in eukaryotic and prokaryotic organisms. Under conditions of high ammonia concentration, this deamination reaction is reversible and hence there is considerable interest in the development of PALs as biocatalysts for the enantioselective synthesis of non-natural amino acids. Herein the discovery of a previously unobserved competing MIO-independent reaction pathway, which proceeds in a non-stereoselective manner and results in the generation of both L- and D-phenylalanine derivatives, is described. The mechanism of the MIO-independent pathway is explored through isotopic-labeling studies and mutagenesis of key active-site residues. The results obtained are consistent with amino acid deamination occurring by a stepwise E1cB elimination mechanism. All manner of things: A competing MIO-independent (MIO=4-methylideneimidazole-5-one) reaction pathway has been identified for phenylalanine ammonia lyases (PALs), which proceeds in a non-stereoselective manner, resulting in the generation of D-phenylalanine derivatives. The mechanism of D-amino acid formation is explored through isotopic-labeling studies and mutagenesis of key active-site residues.
Fluorine Radiolabelling Process
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Paragraph 0521, (2013/07/31)
The invention relates to a process for producing a process for producing an 18F-labelled compound, the process comprising treating a compound of formula (I) wherein EDG is an electron-donating group selected from —OH, —OR4, —NHR5 and —NR55R5; R1, R2, X1 and X2 are as defined herein; and R3 is selected from H, X3 and X4, wherein X3 is a monodentate cleavable surrogate group, and X4 is a bidentate cleavable surrogate group which is bonded (a) to said X1 or X2 and (b) to the ring carbon atom para to EDG; with [18F]fluoride in the presence of an oxidant, thereby producing, when R3 in the compound of formula (I) is H, an 18F-labelled compound of formula (II), wherein EDG is as defined above and R1, R2, X1 and X2 are as defined herein; or thereby producing, when R3 in the compound of formula (I) is said monodentate cleavable surrogate group X3, a compound of formula (IIa), wherein EDG′ is O, NR5, —NR55R5 or [OR4]+, and wherein R4, R5, R55, R1, R2, X1, X2 and X3 are as defined herein; or thereby producing, when R3 in the compound of formula (I) is said bidentate cleavable surrogate group X4, a compound of formula (IIc) or a compound of formula (IId), wherein EDG′ is O, NR5, —NR55R5 or [OR4]+, and wherein R4, R5, R55, R1, R2, X1, X2 and X4 are as defined herein
FLUORINE RADIOLABELLING PROCESS
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Page/Page column 100, (2012/02/01)
The invention relates to a process for producing a process for producing an 18F-labelled compound, the process comprising treating a compound of formula (I): wherein EDG is an electron-donating group selected from -OH, -OR4, -NHR5 and -NR55R5; R1, R2, X1 and X2 are as defined herein; and R3 is selected from H, X3 and X4, wherein X3 is a monodentate cleavable surrogate group, and X4 is a bidentate cleavable surrogate group which is bonded (a) to said X or X and (b) to the ring carbon atom para to EDG; with [18F]fluoride in the presence of an oxidant, thereby producing, when R3 in the compound of formula (I) is H, an 18F-labelled compound of formula (II), wherein EDG is as defined above and R1, R2, X1 and X2 are as defined herein; or thereby producing, when R3 in the compound of formula (I) is said monodentate cleavable surrogate group X4, a compound of formula (Ilc), wherein EDG' is O, NR5, -NR55R5 or [OR4]+, and wherein R4, R5, R55, R1, R2, X1, X2 and X3 are as defined herein; or thereby producing, when R3 in the compound of formula (I) is said bidentate cleavable surrogate group X4, a compound of formula (IIc) or a compound of formula (IId), wherein EDG' is O, NR5, -NR55R5 or [OR4]+, and wherein R4, R5, R55, R1, R2, X1, X2 and X4 are as defined herein.
Identification of phenylalanine 3-hydroxylase for meta -tyrosine biosynthesis
Zhang, Wenjun,Ames, Brian D.,Walsh, Christopher T.
scheme or table, p. 5401 - 5403 (2012/06/15)
Phenylalanine hydroxylase (PheH) is an iron(II)-dependent enzyme that catalyzes the hydroxylation of aromatic amino acid l-phenylalanine (l-Phe) to l-tyrosine (l-Tyr). The enzymatic modification has been demonstrated to be highly regiospecific, forming proteinogenic para-Tyr (p-Tyr) exclusively. Here we biochemically characterized the first example of a phenylalanine 3-hydroxylase (Phe3H) that catalyzes the synthesis of meta-Tyr (m-Tyr) from Phe. Subsequent mutagenesis studies revealed that two residues in the active site of Phe3H (Cys187 and Thr202) contribute to C-3 rather than C-4 hydroxylation of the phenyl ring. This work sets the stage for the mechanistic and structural study of regiospecific control of the substrate hydroxylation by PheH.
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%.
SUBSTITUTED HYDROXYPHENYLAMINE COMPOUNDS
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Page/Page column 41, (2010/06/11)
The present invention relates to new substituted hydroxyphenylamine based modulators of hormone and/or pigment levels, pharmaceutical compositions thereof, and methods of use thereof. Formula (I).
Optimized synthesis of L-m-tyrosine suitable for chemical scale-up
Humphrey, Cara E.,Furegati, Markus,Laumen, Kurt,Vecchia, Luigi La,Leuten, Thomas,Constanze D Mueller-Hartwieg,Voegtle, Markus
, p. 1069 - 1075 (2012/12/30)
This paper demonstrates how L-m-tyrosine 1 can be synthesized on larger-scale via enzyme-catalyzed kinetic resolution of N-acyl m-tyrosine methyl ester 4. N-Acyl m-tyrosme methyl ester 4 was prepared by a modification of Erlenmeyer's azalactone synthesis followed by hydrogenation of the resultant dehydroamino acid 12. The optimized four-step synthesis utilizes cheap and readily available starting materials and circumvents difficult purification protocols.
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].
