587-33-7Relevant articles and documents
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
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.
