2078-15-1Relevant articles and documents
Investigation of the substrate range of CYP199A4: Modification of the partition between hydroxylation and desaturation activities by substrate and protein engineering
Bell, Stephen G.,Zhou, Ruimin,Yang, Wen,Tan, Adrian B. H.,Gentleman, Alexander S.,Wong, Luet-Lok,Zhou, Weihong
, p. 16677 - 16688 (2013/03/28)
The cytochrome P450 enzyme CYP199A4, from Rhodopseudomonas palustris HaA2, can efficiently demethylate 4-methoxybenzoic acid. It is also capable of oxidising a range of other related substrates. By investigating substrates with different substituents and ring systems we have been able to show that the carboxylate group and the nature of the ring system and the substituent are all important for optimal substrate binding and activity. The structures of the veratric acid, 2-naphthoic acid and indole-6-carboxylic acid substrate-bound CYP199A4 complexes reveal the substrate binding modes and the side-chain conformational changes of the active site residues to accommodate these larger substrates. They also provide a rationale for the selectivity of product oxidation. The oxidation of alkyl substituted benzoic acids by CYP199A4 is more complex, with desaturation reactions competing with hydroxylation activity. The structure of 4-ethylbenzoic acid-bound CYP199A4 revealed that the substrate is held in a similar position to 4-methoxybenzoic acid, and that the C β C-H bonds of the ethyl group are closer to the heme iron than those of the Cα (3.5 vs. 4.8 A?). This observation, when coupled to the relative energies of the reaction intermediates, indicates that the positioning of the alkyl group relative to the heme iron may be critical in determining the amount of desaturation that is observed. By mutating a single residue in the active site of CYP199A4 (Phe185) we were able to convert the enzyme into a 4-ethylbenzoic acid desaturase. Engineering a P450 desaturase: The substrate range of CYP199A4 from Rhodopseudomonas palustris was investigated. The partition between the hydroxylation and desaturation activities of 4-ethylbenzoic acid was studied by changing the substrate and by mutation. The activity of CYP199A4 with 4-ethylbenzoic acid was changed to a desaturase by a single mutation at F185. Copyright
Metabolic pathways of 4-[(3-methoxyphenyl)methyl]-2,2,6,6-tetramethyl-1-oxa-4-aza-2,6-disila cyclohexane (MPSC) hydrochloride, a silicon-containing xenobiotic, in rat, dog, and man
Dain,Nicoletti
, p. 951 - 961 (2007/10/03)
The metabolic pathways of Sandoz compound 58-112, 4-[(3-methoxyphenyl)methyl]-2,2,6,6-tetramethyl-1-oxa-4-aza-2,6-disila cyclohexane (MPSC) hydrochloride were evaluated in rat, dog, and man after a single oral dose. In rat, dog and man the major route of elimination was renal. In the dog, renal excretion of unchanged MPSC represented a substantial portion of the dose whereas in rat and man MPSC was completely metabolized prior to excretion. In rat and man, the major end-product metabolite was 3'-[{(hydroxydimethylsilyl)methylamino}methyl]-phenol glucuronide; 4-[(3-hydroxyphenyl)-methyl]-2,2,6,6-tetramethyl-1-oxa-4-aza-2,6-disil acyclohexane and 4-[(4-hydroxy-3-methoxyphenyl)methyl]-2,2,6,6-tetramethyl-1-oxa-4-aza- 2,6-disilacyclohexane and their conjugates were also present. In dog, the major end-product metabolites were the hippurate of 3-methoxybenzoic acid and 3-hydroxybenzoic acid.
ASSIGNMENT OF 29Si NMR LINES AND DETERMINATION OF 29Si-13C COUPLING CONSTANTS IN PERTRIMETHYLSILYLATED LIGNIN-RELATED PHENOL-CARBOXYLIC ACIDS BY SELECTIVE HETERONUCLEAR INADEQUATE METHOD
Schraml, Jan,Past, Jaan,Puskar, Jueri,Pehk, Tonis,Lippmaa, Endel,Brezny, Robert
, p. 1985 - 1991 (2007/10/02)
Selective heteronuclear (Si-C) INADEQUATE method has been successfully used to assign all 29Si chemical shifts in six pertrimethylsilylated lignin model compounds.Empirical assignment of the lines in the region δ=23-25 to trimethylsilyl esters of carboxyl
