Metabolic engineering and control analysis for production of aromatics: Role of transaldolase

Lu, Jia-ling; Liao, James C.

doi:10.1002/(sici)1097-0290(19970120)53:2<132::aid-bit2>3.0.co;2-p

Cited by 63 publications

(38 citation statements)

References 15 publications

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“…These include: the removal of the enzyme or its inhibition to eliminate a competitive pathway (Green et al, 1996;Gasson et al, 1996;Shimada et al, 1998) or a toxic byproduct Cameron et al, 1998, Chaplen at al., 1996; the amplification of a gene or group of genes to improve the synthesis of existing products (Pines et al, 1997;Shimada et al, 1998;Lu and Liao;; the expression of an heterologous enzyme(s) to extend the substrate range (Prieto et al, 1996;Panke et al, 1998;Sprenger, 1996), to produce novel product (Chopra and Vageeshbabu, 1996;Hershberger, 1996;Ingram et al, 1998;Misawa and Shimada, 1998;Poirier et al, 1995;Stassi et al, 1998), to provide pathways for the degradation of toxic compounds (Chen and Wilson, 1997;Keasling et al, 1998;Xu et al, 1996), or to design a more environmentally resistant plant (Smirnoff, 1998). Alternatively, the deregulation of existing enzymes might be necessary to overcome the existing control mechanisms of a rigid node.…”

Section: Selection Of the Methods Of Genetic Modificationmentioning

confidence: 99%

Genetic and metabolic engineering

Yang¹,

Bennett²,

San³

1998

Electron. J. Biotechnol.

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Recent advances in molecular biology techniques, analytical methods and mathematical tools have led to a growing interest in using metabolic engineering to redirect metabolic fluxes for industrial and medical purposes. Metabolic engineering is referred to as the directed improvement of cellular properties through the modification of specific biochemical reactions or the introduction of new ones, with the use of recombinant DNA technology (Stephanopoulos, 1999). This multidisciplinary field draws principles from chemical engineering, biochemistry, molecular and cell biology, and computational sciences. The aim of this article is to give an overview of the various strategies and tools available for metabolic engineers and to review some of the recent work that has been conducted in our laboratories in the metabolic engineering area.Metabolic engineering is generally referred to as the targeted and purposeful alteration of metabolic pathways found in an organism in order to better understand and utilize cellular pathways for chemical transformation, energy transduction, and supramolecular assembly (Lessard, 1996). This multidisciplinary field draws principles from chemical engineering, computational sciences, biochemistry, and molecular biology. In essence, metabolic engineering is the application of engineering principles of design and analysis to the metabolic pathways in order to achieve a particular goal. This goal may be to increase process productivity, as in the case in production of antibiotics, biosynthetic precursors or polymers, or to extend metabolic capability by the addition of extrinsic activities for chemical production or degradation. Previous strategies to attain these goals seem more of an art with experimentation by trial-and-error. Two papers in the early 1990s advocated the switch from this artistic approach to a more systematic and rational approach (Bailey, 1991, Stephanopoulos and Vanillo, 1991). This scientific approach would involve the use of recombinant DNA technology and a better understanding of cellular physiology to modify intermediary metabolism. Several reviews on metabolic engineering cover general

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Section: Selection Of the Methods Of Genetic Modificationmentioning

confidence: 99%

Genetic and metabolic engineering

Yang¹,

Bennett²,

San³

1998

Electron. J. Biotechnol.

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“…However, all attempts to produce large quantities of ethanol by means of recombinant yeasts overexpressing TK and TA have failed thus far [e.g. 96,168]. Nonetheless, TK ®nds an increasing number of applications for industrial purposes, in particular in the synthesis of chemicals.…”

Section: Industrial Uses Of Tkmentioning

confidence: 99%

Properties and functions of the thiamin diphosphate dependent enzyme transketolase

Schenk

Duggleby

Nixon

1998

The International Journal of Biochemistry & Cell Biology

223

164

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This review highlights recent research on the properties and functions of the enzyme transketolase, which requires thiamin diphosphate and a divalent metal ion for its activity. The transketolase-catalysed reaction is part of the pentose phosphate pathway, where transketolase appears to control the non-oxidative branch of this pathway, although the overall¯ux of labelled substrates remains controversial. Yeast transketolase is one of several thiamin diphosphate dependent enzymes whose three-dimensional structures have been determined. Together with mutational analysis these structural data have led to detailed understanding of thiamin diphosphate catalysed reactions. In the homodimer transketolase the two catalytic sites, where dihydroxyethyl groups are transferred from ketose donors to aldose acceptors, are formed at the interface between the two subunits, where the thiazole and pyrimidine rings of thiamin diphosphate are bound. Transketolase is ubiquitous and more than 30 full-length sequences are known. The encoded protein sequences contain two motifs of high homology; one common to all thiamin diphosphate-dependent enzymes and the other a unique transketolase motif. All characterised transketolases have similar kinetic and physical properties, but the mammalian enzymes are more selective in substrate utilisation than the nonmammalian representatives. Since products of the transketolase-catalysed reaction serve as precursors for a number of synthetic compounds this enzyme has been exploited for industrial applications. Putative mutant forms of transketolase, once believed to predispose to disease, have not stood up to scrutiny. However, a modi®cation of transketolase is a marker for Alzheimer's disease, and transketolase activity in erythrocytes is a measure of thiamin nutrition. The cornea contains a particularly high transketolase concentration, consistent with the proposal that pentose phosphate pathway activity has a role in the removal of light-generated radicals. #

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“…Furthermore, overexpression of genes encoding PEP synthase, PEP carboxykinase, and the use of an ATP-dependent glucose phosphorylation system instead of the PEP-dependent phosphotransferase system had positive effects on the availability of shikimic acid pathway precursor PEP (Patnaik et al, 1995, Liao, 1996, Gulevich et al, 2004. In E. coli, the availability of erythrose-4-phosphate could be increased by overproduction of transketolase and transaldolase or by phosphoglucose isomerase gene disruption (Draths & Frost, 1990, Draths et al, 1992, Lu & Liao, 1997, Mascarenhas et al, 1991, Frost, 1992. Up to now, only Lphenylalanine production from glycerol has been shown, but results might be transferable to the other aromatic amino acids.…”

Section: Amino Acidsmentioning

confidence: 99%