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Alleviation of feedback inhibition in Saccharomyces cerevisiae aromatic amino acid biosynthesis: Quantification of metabolic impact

Paper ID Volume ID Publish Year Pages File Format Full-Text
31863 44846 2008 13 PDF Available
Title
Alleviation of feedback inhibition in Saccharomyces cerevisiae aromatic amino acid biosynthesis: Quantification of metabolic impact
Abstract

A quantitative analysis of the impact of feedback inhibition on aromatic amino acid biosynthesis was performed in chemostat cultures of Saccharomyces cerevisiae. Introduction of a tyrosine-insensitive allele of ARO4 (encoding 3-deoxy-d-arabino-heptulosonate-7-phosphate synthase) caused a three-fold increase of intracellular phenylalanine and tyrosine concentrations. These amino acids were not detected extracellularly. However, an over 100-fold increase of the extracellular levels of phenylacetate, phenylethanol and their para-hydroxyl analogues was observed. The total increase of the flux through the aromatic pathway was estimated to be over four-fold. Individual overexpression of either the wild-type or feedback insensitive allele of ARO7 (encoding chorismate mutase had no significant impact. However when they were combined with the Tyr-insensitive ARO4 allele in combination with the Tyr-insensitive ARO4 allele, extracellular concentrations of aromatic compounds were increased by over 200-fold relative to the reference strain, corresponding to a 4.5-fold increase of the flux through the aromatic amino acid biosynthesis pathway. Elimination of allosteric control on these two key reactions in aromatic amino acid metabolism significantly affected intracellular concentrations of several non-aromatic amino acids. This broader impact of amino acid biosynthesis presents a challenge in rational optimization of the production of specific amino acids and derived flavour compounds.

Keywords
Chemostat culture; Saccharomyces cerevisiae; Aromatic amino acid biosynthesis; Chorismate mutase; DAHP synthase; Feedback inhibition
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Alleviation of feedback inhibition in Saccharomyces cerevisiae aromatic amino acid biosynthesis: Quantification of metabolic impact
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Publisher
Database: Elsevier - ScienceDirect
Journal: Metabolic Engineering - Volume 10, Issues 3–4, May–July 2008, Pages 141–153
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us