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Chapter
A New Intermediate in TPNH-Linked Flavoproteins
The early studies of Michaelis et. al. (1) clearly indicated that partial reduction of the flavin coenzymes led to the production of colored radical intermediates. Except for the catio-nic radical, which is produ...
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Chapter
Interactions of adenosylmethionine with methylenetetrahydrofolate reductase
Commercial preparations of AdoMet are isolated from yeast, and the AdoMet has the configuration of the natural diastereoisomer at both the sulfonium pole and the methionyl substituent. However, such preparatio...
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Chapter
The Role of Folylpolyglutamates in the Regulation of Folate Metabolism
Folylpolyglutamates have been shown to function as potent inhibitors, relative to the corresponding monoglutamates, of two enzymes involves in the metabolism of methylenetetrahydrofolate (CH2-H4folate) in mammali...
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Chapter
Cobalamin-Dependent and Cobalamin-Independent Methionine Synthases in Escherichia coli: Two Solutions to the Same Chemical Problem
Two genes encoding proteins with methionine synthase activity are found in Escherichia coli. Both enzymes use methyltetrahydrofolate as a methyl donor to catalyze the conversion of homocysteine to methionine, as ...
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Article
Human methylenetetrahydrofolate reductase: isolation of cDNA, map** and mutation identification
Methylenetetrahydrofolate reductase (MTHFR) catalyses the reduction of methylenetetrahydrofolate to methyltetrahydrofolate, a cofactor for homocysteine methylation to methionine. MTHFR deficiency, an autosomal...
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Chapter
Methylenetetrahydrofolate Reductase: Comparison of the Enzyme from Mammalian and Bacterial Sources
Methylenetetrahydrofolate reductase catalyzes the reduction of methylenetetrahydrofolate to methyl-tetrahydrofolate, which serves as the methyl donor for the conversion of homocysteine to methionine in the rea...
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Article
The structure and properties of methylenetetrahydrofolate reductase from Escherichia coli suggest how folate ameliorates human hyperhomocysteinemia
Elevated plasma homocysteine levels are associated with increased risk for cardiovascular disease and neural tube defects in humans. Folate treatment decreases homocysteine levels and dramatically reduces the ...
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Article
Domain alternation switches B12-dependent methionine synthase to the activation conformation
B12-dependent methionine synthase (MetH) from Escherichia coli is a large modular protein that uses bound cobalamin as an intermediate methyl carrier. Major domain rearrangements have been postulated to explain h...
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Chapter
Making Methionine: A Love Affair with Folate
I am deeply honored to be chosen as the Frederick Gowland Hopkins lecturer by my friends and colleagues. The honor is particularly special for me because my father traveled from New York to Cambridge to do his...
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Article
Effector regulation in a monomeric enzyme
The monomeric B12-dependent ribonucleotide reductase from L. leichmannii has the central 10-stranded α/β-barrel found in all ribonucleotide reductases but incorporates two distinctive structural features, a novel...
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Article
Open AccessIntegration of regulatory signals through involvement of multiple global regulators: control of the Escherichia coli gltBDF operon by Lrp, IHF, Crp, and ArgR
The glutamate synthase operon (gltBDF) contributes to one of the two main pathways of ammonia assimilation in Escherichia coli. Of the seven most-global regulators, together affecting expression of about half of ...