Hexokinase of Escherichia coli. Assay of Enzyme Activity and Adaptation to Growth in Various Media

Pakoskey, Anna M.; Lesher, Eileen C.; Scott, Dwight B. McNair

doi:10.1099/00221287-38-1-73

Cited by 15 publications

(8 citation statements)

References 2 publications

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“…All participants were offered group-implemented lifestyle sessions prior to the start of DPPOS, including those who had been randomized to the intensive lifestyle arm during the DPP (22). Open-label metformin was also continued in participants initially randomized to receive metformin (850 mg twice daily as tolerated) during the DPPOS, unless discontinued for the development of diabetes requiring management outside of the protocol, or for reasons of safety and/or tolerability.…”

Section: Methodsmentioning

confidence: 99%

Regression From Prediabetes to Normal Glucose Regulation Is Associated With Reduction in Cardiovascular Risk: Results From the Diabetes Prevention Program Outcomes Study

et al. 2014

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OBJECTIVERestoration of normal glucose regulation (NGR) in people with prediabetes significantly decreases the risk of future diabetes. We sought to examine whether regression to NGR is also associated with a long-term decrease in cardiovascular disease (CVD) risk.RESEARCH DESIGN AND METHODSThe Framingham (2008) score (as an estimate of the global 10-year CVD risk) and individual CVD risk factors were calculated annually for the Diabetes Prevention Program Outcomes Study years 1–10 among those patients who returned to NGR at least once during the Diabetes Prevention Program (DPP) compared with those who remained with prediabetes or those in whom diabetes developed during DPP (N = 2,775).RESULTSThe Framingham scores by glycemic exposure did not differ among the treatment groups; therefore, pooled estimates were stratified by glycemic status and were adjusted for differences in risk factors at DPP baseline and in the treatment arm. During 10 years of follow-up, the mean Framingham 10-year CVD risk scores were highest in the prediabetes group (16.2%), intermediate in the NGR group (15.5%), and 14.4% in people with diabetes (all pairwise comparisons P < 0.05), but scores decreased over time for those people with prediabetes (18.6% in year 1 vs. 15.9% in year 10, P < 0.01). The lower score in the diabetes group versus other groups, a declining score in the prediabetes group, and favorable changes in each individual risk factor in all groups were explained, in part, by higher or increasing medication use for lipids and blood pressure.CONCLUSIONSPrediabetes represents a high-risk state for CVD. Restoration of NGR and/or medical treatment of CVD risk factors can significantly reduce the estimated CVD risk in people with prediabetes.

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Section: Methodsmentioning

confidence: 99%

Regression From Prediabetes to Normal Glucose Regulation Is Associated With Reduction in Cardiovascular Risk: Results From the Diabetes Prevention Program Outcomes Study

et al. 2014

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“…Incorporation and respiratory studies showed that exogenous glucose was metabolized and could contribute up to 46% of the total cell material. The inclusion of glucose in the growth medium has been shown to increase, by up to three-fold, hexokinase activity in Escherichia coli (Scott & Chu, 1959) and Clostridium perfringens (Ivanov, 1959) and glucose-6-phosphate dehydrogenase in Pseudomonas aeruginosa (Hamilton & Dawes, 1960) and E. coli (Pakoskey, Lesher & Scott, 1965).…”

Section: I55 Discussionmentioning

confidence: 99%

The Incorporation and Metabolism of Glucose by Anabaena variabilis

Pearce

Carr

1968

Journal of General Microbiology

101

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SUMMARYThe incorporation and metabolism of glucose by the blue-green alga Anabaena variabilis is described. Experiments with [14C]glucose indicated that this compound contributed up to 46 yo of the total dry wt of organism.Respiratory studies with [ I -~~C ] and [6J4C] showed that the pentose phosphate pathway was the major route of glucose dissimilation. No evidence of alteration in enzyme concentration after growth in the presence of glucose was found in the ten examples of glycolytic and pentose phosphate pathway enzymes examined. Enzymes from both pathways were affected by the endproducts. These results are discussed in relation to autotrophic metabolism in blue-green algae.

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“…The following enzymes were examined: acetate kinase (25), fumarate reductase (33), glucokinase (36), isocitrate dehydrogenase (44), isocitrate lyase (12), PEP carboxylase (29), and pyruvate carboxylase (37). For all of these enzymes, 1 U of enzyme activity is the quantity of enzyme that converts 1 mol of substrate to (18) product per min.…”

Section: Methodsmentioning

confidence: 99%

Effects of Growth Mode and Pyruvate Carboxylase on Succinic Acid Production by Metabolically Engineered Strains of Escherichia coli

Vemuri

Eiteman

Altman

2002

Appl Environ Microbiol

233

148

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Escherichia coli NZN111, which lacks activities for pyruvate-formate lyase and lactate dehydrogenase, and AFP111, a derivative which contains an additional mutation in ptsG (a gene encoding an enzyme of the glucose phophotransferase system), accumulate significant levels of succinic acid (succinate) under anaerobic conditions. Plasmid pTrc99A-pyc, which expresses the Rhizobium etli pyruvate carboxylase enzyme, was introduced into both strains. We compared growth, substrate consumption, product formation, and activities of seven key enzymes (acetate kinase, fumarate reductase, glucokinase, isocitrate dehydrogenase, isocitrate lyase, phosphoenolpyruvate carboxylase, and pyruvate carboxylase) from glucose for NZN111, NZN111/pTrc99A-pyc, AFP111, and AFP111/pTrc99A-pyc under both exclusively anaerobic and dual-phase conditions (an aerobic growth phase followed by an anaerobic production phase). The highest succinate mass yield was attained with AFP111/pTrc99A-pyc under dual-phase conditions with low pyruvate carboxylase activity. Dual-phase conditions led to significant isocitrate lyase activity in both NZN111 and AFP111, while under exclusively anaerobic conditions, an absence of isocitrate lyase activity resulted in significant pyruvate accumulation. Enzyme assays indicated that under dual-phase conditions, carbon flows not only through the reductive arm of the tricarboxylic acid cycle for succinate generation but also through the glyoxylate shunt and thus provides the cells with metabolic flexibility in the formation of succinate. Significant glucokinase activity in AFP111 compared to NZN111 similarly permits increased metabolic flexibility of AFP111. The differences between the strains and the benefit of pyruvate carboxylase under both exclusively anaerobic and dual-phase conditions are discussed in light of the cellular constraint for a redox balance.

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Hexokinase of Escherichia coli. Assay of Enzyme Activity and Adaptation to Growth in Various Media

Cited by 15 publications

References 2 publications

Regression From Prediabetes to Normal Glucose Regulation Is Associated With Reduction in Cardiovascular Risk: Results From the Diabetes Prevention Program Outcomes Study

Regression From Prediabetes to Normal Glucose Regulation Is Associated With Reduction in Cardiovascular Risk: Results From the Diabetes Prevention Program Outcomes Study

The Incorporation and Metabolism of Glucose by Anabaena variabilis

Effects of Growth Mode and Pyruvate Carboxylase on Succinic Acid Production by Metabolically Engineered Strains of Escherichia coli

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