Format

Send to

Choose Destination
See comment in PubMed Commons below
Biochem J. 1992 Oct 15;287 ( Pt 2):473-9.

A strategy for increasing an in vivo flux by genetic manipulations. The tryptophan system of yeast.

Author information

1
Mikrobiologisches Institut, Eidgenössisch Technische Hochschule, Zürich, Switzerland.

Abstract

Decreases in enzyme activity often have little effect on the flux carried by the pathway. Similarly, up-modulation of single genes, and hence of the dependent enzyme concentrations, is frequently found to be ineffective in increasing the flux in the pathway in which the enzyme occurs. This insensitivity to enzyme variation is demonstrated experimentally for five separate enzymes in the tryptophan synthesis system of yeast, first by down-modulation of the gene dose and secondly by increasing the dose using multi-copy vectors. Such a lack of response is discussed in terms of the concepts of metabolic control analysis. When these five enzymes, however, were simultaneously increased by a multi-copy vector carrying all five genes, a substantial elevation of the flux to tryptophan was observed. These findings revealed a new phenomenon, namely the more than additive effects on the flux of simultaneous elevations of several enzyme activities.

PMID:
1445205
PMCID:
PMC1133189
[Indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Support Center