Threonine overproduction in yeast strains carrying the HOM3-R2 mutant allele under the control of different inducible promoters.
Appl Environ Microbiol
; 65(1): 110-6, 1999 Jan.
Article
en En
| MEDLINE
| ID: mdl-9872767
ABSTRACT
The HOM3 gene of Saccharomyces cerevisiae codes for aspartate kinase, which plays a crucial role in the regulation of the metabolic flux that leads to threonine biosynthesis. With the aim of obtaining yeast strains able to overproduce threonine in a controlled way, we have placed the HOM3-R2 mutant allele, which causes expression of a feedback-insensitive enzyme, under the control of four distinctive regulatable yeast promoters, namely, PGAL1, PCHA1, PCYC1-HSE2, and PGPH1. The amino acid contents of strains bearing the different constructs were analyzed both under repression and induction conditions. Although some differences in overall threonine production were found, a maximum of around 400 nmol/mg (dry weight) was observed. Other factors, such as excretion to the medium and activity of the catabolic threonine/serine deaminase, also affect threonine accumulation. Thus, improvement of threonine productivity by yeast cells would probably require manipulation of these and other factors.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Saccharomyces cerevisiae
/
Treonina
/
Genes Fúngicos
/
Mutación
Idioma:
En
Revista:
Appl Environ Microbiol
Año:
1999
Tipo del documento:
Article
País de afiliación:
España