Introduction - regulation and control methods for studying metabolism its traditional approaches to metabolic enzyme activity the molecular basis analysis structures in metabolism. (Part contents)

The metabolic network of the catabolic, energy and biosynthetic metabolism Escherichia coli is a paradigmatic case for large genetic networks that functional genomics efforts are beginning to elucidate. To analyse structure previously unknown involving hundreds or thousands components by simple visual inspection impossible, quantitative approaches needed them. We have undertaken graph theoretical analysis E. find this small–world graph, type distinct from both regular random observed in...

Existing theorems from the analysis of metabolic control have been taken and embedded in a simple matrix algebra procedure for calculating flux coefficients enzymes (formerly known as sensitivities) pathway their kinetic properties (their elasticities). New governing branched pathways substrate cycles derived to allow be applied complex configurations. Modifications elasticity terms used equations theoretically justified so that method remains valid with conserved metabolites (for example,...

Abstract We describe the construction and analysis of a genome-scale metabolic model Arabidopsis (Arabidopsis thaliana) primarily derived from annotations in Aracyc database. used techniques based on linear programming to demonstrate following: (1) that is capable producing biomass components (amino acids, nucleotides, lipid, starch, cellulose) proportions observed experimentally heterotrophic suspension culture; (2) approximately only 15% available reactions are needed for this purpose size...

Although leaves have to accommodate markedly different metabolic flux patterns in the light and dark, models of leaf metabolism based on flux-balance analysis (FBA) so far been confined consideration network under continuous light. An FBA framework is presented that solves two phases diel cycle as a single optimization problem and, thus, provides more representative model metabolism. The requirement support continued export sugar amino acids from during night meet overnight cellular...

Metabolic control analyses of glucose utilization were performed for four groups working rat hearts perfused with Krebs-Henseleit buffer containing 10 mM only, or the addition 4 D-beta-hydroxybutyrate/1 acetoacetate, 100 nM insulin (0.05 unit/ml), both. Net glycogen breakdown occurred in group only and was converted to net synthesis presence all additions. The flux [2-3H]glucose through P-glucoisomerase (EC 5.3.1.9) reduced ketones, elevated insulin, unchanged combination. glycolytic ketones...

The requirement for net balance of synthesis, degradation and transport all intermediates in the pathways from glucose to fat imposes constraints on fluxes between different pathways. Linear programming has been used examine interactions these metabolism adipocytes efficiency conversion into fat. circumstances under which excessive ATP synthesis would accompany this have investigated.

The effect of externally applied L-cysteine and glutathione (GSH) on ATP sulphurylase adenosine 5'-phosphosulphate reductase (APR), two key enzymes assimilatory sulphate reduction, was examined in Arabidopsis thaliana root cultures. Addition increasing to the nutrient solution increased internal cysteine, gamma-glutamylcysteine GSH concentrations, decreased APR mRNA, protein extractable activity. An could already be detected at 0.2 mm L-cysteine, whereas significantly affected only 2...

Although epidermal growth factor (EGF) induces transient activation of Ras and the mitogen-activated protein kinase (MAPK) cascade in PC12 cells, whereas nerve (NGF) stimulates sustained activation, basis for these contrasting responses is not known. We have developed a computer simulation EGF-induced MAPK which provides quantitative evidence that feedback inhibition most important determining duration activation. Hence, we propose observed differences EGF NGF signalling can be accounted by...

Abstract Flux is a key measure of the metabolic phenotype. Recently, complete (genome-scale) network models have been established for Arabidopsis (Arabidopsis thaliana), and flux distributions predicted using constraints-based modeling optimization algorithms such as linear programming. While these are useful investigating possible states under different scenarios, it not clear how close to those occurring in vivo. To address this, fluxes were heterotrophic cells compared with estimated...

Summary Flux balance models of metabolism generally utilize synthesis biomass as the main determinant intracellular fluxes. However, constraint alone is not sufficient to predict realistic fluxes in central heterotrophic plant cells because major demand on energy budget due transport costs and cell maintenance. This limitation can be addressed by incorporating steps into metabolic model implementing a procedure that uses P areto optimality analysis explore trade‐off between ATP NADPH...

Abstract We describe the construction and analysis of a genome-scale metabolic model representing developing leaf cell rice (Oryza sativa) primarily derived from annotations in RiceCyc database. used flux balance to determine that represents network capable producing biomass precursors (amino acids, nucleotides, lipid, starch, cellulose, lignin) experimentally reported proportions, using carbon dioxide as sole source. then repeated over range photon values examine responses solutions. The...

The dynamic and steady-state behaviour of a computer simulation the Calvin cycle reactions chloroplast, including starch synthesis degradation, triose phosphate export have been investigated. A major difference compared with previous models is that none reversible are assumed to be at equilibrium. model can exhibit alternate steady states low or high carbon assimilation flux, hysteresis in transitions between induced by environmental factors such as light intensity. enzymes which greatest...

Summary We have compared, in 40 healthy patients, the cardiovascular responses induced by laryngoscopy and intubation with those produced insertion of a laryngeal mask. Anaesthesia was thiopentone maintained enflurane nitrous oxide oxygen; vecuronium used for muscle relaxation. Arterial pressure measured Finapres monitor. The mean maximum increase systolic arterial after tracheal 51.3% compared 22.9% mask (p < 0.01). Increases heart rate were similar, (26.6% v 25.7%) although remained...

The problems of engineering increased flux in metabolic pathways are analyzed terms the understanding provided by control analysis. Over-expression a single enzyme is unlikely to be effective unless it known have high coefficient, which can used as an approximate predictive tool. This likely rule out enzymes subject feedback inhibition, because transfers downstream from inhibited utilizing metabolite. Although abolishing inhibition restore enzyme, also cause large increases concentrations...