James Sumner

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Methylenetetrahydrofolate reductase (MTHFR) catalyses the reduction of methylenetetrahydrofolate to methyltetrahydrofolate, a cofactor for homocysteine methylation to methionine. MTHFR deficiency, an autosomal recessive disorder, results in homocysteinemia. Using degenerate oligonucleotides based on porcine peptide sequence data, we isolated a 90-bp cDNA by(More)
In Escherichia coli, two enzymes catalyze the synthesis of methionine from homocysteine using methyltetrahydrofolate as the donor of the required methyl group: cobalamin-dependent and cobalamin-independent methionine synthases. Comparison of the mechanisms of these two enzymes offers the opportunity to examine two different solutions to the same chemical(More)
Methylenetetrahydrofolate reductase commits tetrahydrofolate-bound one carbon units to use in the regeneration of the methyl group of adenosylmethionine (AdoMet) in eucaryotes and its activity is allosterically inhibited by AdoMet. Limited proteolysis and scanning transmission electron microscopy have been employed to show that the enzyme is a dimer of(More)
A method utilizing NMR spectroscopy has been developed to confirm the identity of bacterial polysaccharides used to formulate a polyvalent pneumococcal polysaccharide vaccine. The method is based on 600 MHz proton NMR spectra of individual serotype-specific polysaccharides. A portion of the anomeric region of each spectrum (5.89 to 4.64 ppm) is compared to(More)
A technique using high performance size exclusion chromatography (HPSEC) with rate nephelometry (RN) detection has been developed to simultaneously measure the relative molecular size and antigenicity of the bacterial polysaccharide components in a multivalent pneumococcal vaccine, PNEUMOVAX 23. This assay was used to establish stability profiles for each(More)
Methylenetetrahydrofolate reductase catalyzes the reduction of methylenetetrahydrofolate to methyltetrahydrofolate, which serves as the methyl donor for the conversion of homocysteine to methionine in the reaction catalyzed by methionine synthase. Recent studies have provided evidence for association of a common polymorphism of methylenetetrahydrofolate(More)
This set of Book Reviews covers Mark Priestley's "A Science of Operations: Machines, Logic and the Invention of Programming" (Springer, 2011) and "Moving Targets: Elliott-Automation and the Dawn of the Computer Age in Britain, 1947—67" by Simon Lavington (Springer, 2011).
Before canals and railways developed as a major transport network, it was seldom profitable to transport beer inland over more than a few miles. In country towns and villages, therefore, beer would be brewed either by a small 'common' brewery that supplied a handful of pubs and private customers, or in an even smaller brew-house attached to the pub itself.(More)
Early microcomputing culture was characterized by a proliferation of other machine-oriented platforms, often aimed at home users. Contemporaneously with Apple, the established electronics firms Commodore and Tandy Radio Shack introduced formulations of the personal computer that long endured, sustained by enthusiastic user communities and vigorous software(More)
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