Xylose fermentation by yeasts

Rizzi, Manfred; Erlemann, Petra; Bui-Thanh, Ngoc-Anh; Dellweg, H.

doi:10.1007/bf00251694

Cited by 3 publications

(2 citation statements)

References 20 publications

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“…1B, however, these values were always in the range of 60–70% of the ALR activities determined with NADPH as coenzyme. This compares very well with a purified xylose reductase from Pichia stipitis , which showed dual coenzyme specificity and for which a constant ratio of NADH‐ to NADPH‐dependent activity of 0.65 has been reported [13].…”

Section: Resultssupporting

confidence: 77%

Induction of aldose reductase and xylitol dehydrogenase activities in Candida tenuis CBS 4435

Kern

Haltrich

Nidetzky

et al. 2006

FEMS Microbiology Letters

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In this study the ability of various sugars and sugar alcohols to induce aldose reductase (xylose reductase) and xylitol dehydrogenase (xylulose reductase) activities in the yeast Candida tenuis was investigated. Both enzyme activities were induced when the organism was grown on D-xylose or L-arabinose as well as on the structurally related sugars D-arabinose or D-lyxose. Mixtures of D-xylose with the more rapidly metabolizable sugar D-glucose resulted in a decrease in the levels of both enzymes formed. These results show that the utilization of D-xylose by C. tenuis is regulated by induction and catabolite repression. Furthermore, the different patterns of induction on distinct sugars suggest that the synthesis of both enzymes is not under coordinate control.

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Section: Resultssupporting

confidence: 77%

Induction of aldose reductase and xylitol dehydrogenase activities in Candida tenuis CBS 4435

Kern

Haltrich

Nidetzky

et al. 2006

FEMS Microbiology Letters

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“…In addition, the ability of some pentose‐fermenting yeasts to ferment xylose anaerobically is linked to the NADH coenzyme specificity of their xylose reductases [3, 6]. Based on initial velocity and product inhibition studies, the P. stipitis xylose reductase has been shown to catalyze the forward reaction via an ordered bi–bi mechanism, with the coenzyme binding first to the enzyme followed by the substrate [7].…”

Section: Introductionmentioning

confidence: 99%

Site-directed mutagenesis of the cysteine residues in the Pichia stipitis xylose reductase

Zhang

Lee

2006

FEMS Microbiology Letters

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Xylose reductase catalyzes the reduction of xylose to xylitol and is known to play a pivotal role in pentose metabolism in yeasts. We previously showed that a cystein residue may be involved in binding of the coenzyme NADPH to the Pichia stipitis xylose reductase through chemical modification studies. The question arose as to which of the three cysteine residues in this enzyme may be involved in coenzyme binding. We cloned the XYL1 gene encoding xylose reductase from P. stipitis into the phagemid pEMBL18(+) suitable for site-directed mutagenesis. Each of the three cysteine residues (Cys19, Cys27 and Cys130) was individually mutated to serine. All three Cys-->Ser variants remained functional, but with reduced catalytic activity. Sensitivity of the P. stipitis xylose reductase to thiol-specific reagents was attributed to both Cys27 and Cys130 residues as substitution of either residue with Ser resulted in a significant but incomplete loss of sensitivity to PCMBS. The apparent Km values of the Cys variants for NADPH, NADH and xylose did not differ from those of the wild-type enzyme isolated from yeast by more than 4-fold. Our results suggest that none of the Cys residues are directly involved in NADPH binding, although Cys130 may reside in or near the coenzyme binding region and might play a role in coenzyme specificity.

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Noncovalent Enzyme−Substrate Interactions in the Catalytic Mechanism of Yeast Aldose Reductase

et al. 1998

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The role of noncovalent interactions in the catalytic mechanism of aldose reductase from the yeast Candida tenuis was determined by steady-state kinetic analysis of the NADH-dependent reduction of various aldehydes, differing in hydrophobicity and the hydrogen bonding capability with the binary enzyme-NADH complex. In a series of aliphatic aldehydes, substrate hydrophobicity contributes up to 13.7 kJ/mol of binding energy. The aldehyde binding site of aldose reductase appears to be 1.4 times more hydrophobic than n-octanol and can accommodate a linear alkyl chain with at least seven methylene groups (approximately 14 A in length). Binding energy resulting from interactions at positions 3-6 of the aldehyde is distributed between increasing the catalytic constant 2.6-fold and decreasing the apparent dissociation constant 59-fold. Hydrogen bonding interactions of the enzyme nucleotide complex with the C-2(R) hydroxyl group of the aldehyde are crucial to transition state binding and contribute up to 17 kJ/mol of binding energy. A comparison of the kinetic data of yeast aldose reductase, a key enzyme in the metabolism of D-xylose, and human aldose reductase, a presumably perfect detoxification catalyst [Grimshaw, C. E. (1992) Biochemistry 31, 10139], clearly reflects these differences in physiological function.

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Xylose fermentation by yeasts

Cited by 3 publications

References 20 publications

Induction of aldose reductase and xylitol dehydrogenase activities in Candida tenuis CBS 4435

Induction of aldose reductase and xylitol dehydrogenase activities in Candida tenuis CBS 4435

Site-directed mutagenesis of the cysteine residues in the Pichia stipitis xylose reductase

Noncovalent Enzyme−Substrate Interactions in the Catalytic Mechanism of Yeast Aldose Reductase

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