The Purification and Properties of Thymidylate Synthetase from Chick Embryo Extracts

Lorenson, Mary Y.; Maley, Gladys F.; Maley, Frank

doi:10.1016/s0021-9258(18)95914-4

Cited by 115 publications

(48 citation statements)

References 38 publications

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“…In ECTS-dTMP-H2folate, water07 is 3.4 A from C7 and is nearly aligned with the it orbital, with an angle of 114°between C5 to C7 and C7 to water07, in a good position to add to a C7 methylene (optimum 90°). However, the C6 of the pterin moiety, the source of hydride transfer in the TS reaction (Lorenson et al, 1967), remains exquisitely positioned in the active site of the product complex, to have been available for hydride transfer to the C7 methylene. It is 3.6 A away from the C7 methyl group, making an angle of 85°with the C5 and Cl bond of dTMP.…”

Section: Discussionmentioning

confidence: 99%

Water-mediated substrate/product discrimination: The product complex of thymidylate synthase at 1.83 .ANG.

Fauman¹,

Rutenber²,

Maley³

et al. 1994

Biochemistry

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In an irreversible enzyme-catalyzed reaction, strong binding of the products would lead to substantial product inhibition. The X-ray crystal structure of the product complex of thymidylate synthase (1.83-A resolution, R factor = 0.183 for all data between 7.0 and 1.83 A) identifies a bound water molecule that serves to disfavor binding of the product nucleotide, dTMP. This water molecule is hydrogen bonded to absolutely conserved Tyr 146 (using the Lactobacillus casei numbering system) and is displaced by the C7 methyl group of the reaction product thymidylate. The relation between this observation and kinetic and thermodynamic values is discussed. The structure reveals a carbamate modified N-terminus that binds in a highly conserved site, replaced by side chains that can exploit the same site in other TS sequences. The enzyme-products complex is compared to the previously determined structure of enzyme-substrate-cofactor analog. This comparison reveals changes that occur between the first covalent complex formed between enzyme and substrate with an inhibitory cofactor analog and the completed reaction. The almost identical arrangement of ligands in these two structures contributes to our model for the TS reaction and verifies the physiological relevance of the mode in which potent inhibitors bind to this target for rational drug design.

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Section: Discussionmentioning

confidence: 99%

Water-mediated substrate/product discrimination: The product complex of thymidylate synthase at 1.83 .ANG.

Fauman¹,

Rutenber²,

Maley³

et al. 1994

Biochemistry

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“…spectra were recorded on Pye Unicam SP800, SP500, and SP1800 spectrophotometers and specific rotations were determined using a Perkin-Elmer 241 polarimeter with a 1 dm path length cell. (5).-This compound was prepared by the following modification of the method of Blakley." The pH of a solution of ascorbic acid (20 g, 0.114 mol) in deaerated water (100 ml) was adjusted to pH 6 with IM-aqueous sodium hydroxide under nitrogen.…”

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confidence: 99%

Stereochemistry of reduction of the vitamin folic acid by dihydrofolate reductase

Charlton¹,

Young²,

Birdsall³

et al. 1985

J. Chem. Soc., Perkin Trans. 1

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Reduction of the vitamin folic acid (6) to the coenzyme 5,6,7,8-tetrahydrofolic acid ( I ) by the enzyme dihydrofolate reductase is shown to involve transfer of the 4-pro R hydrogen of NADPH to the same face at both C-6 and C-7 of the pteridine system (the re face at C-6 and the siface at C-7). The orientations of the pteridine system of folic acid (6) and of dihydrofolic acid (5) when bound to the enzyme are different from the orientation of the pteridine ring of the anti-cancer drug methotrexate (I I ) when bound to this enzyme.

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“…In the preparation of the 9-(phenylhydrazono)tetrahydropyridopyrimidine-3-acrylic acids 62, 64, 66, and 68, the 9-[(dimethylamino)methylene]-3-formylpyridopyrimidines 51-547 were reacted with phenyldiazonium (7) Horváth, Á.; Hermecz, I.; Vasvári-Debreczy, L.; Simon, K.;…”

mentioning

confidence: 99%

Nitrogen bridgehead compounds. 44. New antiallergic 4H-pyrido[1,2-a]pyrimidin-4-ones. 4

Hermecz¹,

Horváth²,

Mészáros³

et al. 1984

J. Med. Chem.

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The weak antiallergic activity of 6-methyl-4-oxo-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidine-3-carbox yli c acid (1) in the rat reaginic passive cutaneous anaphylaxis test was enhanced by the introduction of an (arylamino)methylene moiety into position 9 of the pyridopyrimidine ring. Compound 34, (+)-6(S)-methyl-9-[(m-methylphenyl)-hydrazono]-4-oxo-4H-pyrido[1,2 -a] pyrimidine-3-carboxylic acid, displayed about 10 000 times the activity of the starting compound 1. A structure-activity relationship study of 9-[(arylamino)methylene]tetrahydropyridopyrimidine-3-carb ox ylic acids resulted in conclusions similar to those found for the 9-(arylhydrazono)tetrahydro-and 9-(arylamino)dihydropyridopyrimidine series. Replacement of the 3-carboxy group of 9-(phenylhydrazono)-tetrahydropyridopyrimidin-4-ones with an acrylic acid moiety caused slight increases in potency. In the 6-methyl-substituted series, a high stereospecificity was observed between the enantiomers with 6S and 6R absolute configurations, the former being responsible for the antiallergic activity. The effects of some 9-[(arylamino)-methylene]tetrahydropyridopyrimidine-3-car box ylic acids on the rat passive peritoneal anaphylaxis test were also investigated.

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The Purification and Properties of Thymidylate Synthetase from Chick Embryo Extracts

Cited by 115 publications

References 38 publications

Water-mediated substrate/product discrimination: The product complex of thymidylate synthase at 1.83 .ANG.

Water-mediated substrate/product discrimination: The product complex of thymidylate synthase at 1.83 .ANG.

Stereochemistry of reduction of the vitamin folic acid by dihydrofolate reductase

Nitrogen bridgehead compounds. 44. New antiallergic 4H-pyrido[1,2-a]pyrimidin-4-ones. 4

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