Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.1.1.37 (malate dehydrogenase)
 4,591 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

High-malate-producing sake yeasts were isolated from low-maltose-assimilating mutants. A sake yeast Kyokai no. 701 (K-701) was mutagenized with ethyl methanesulfonate. After nystatin treatment, low-maltose-assimilating mutants were selected using a replica plating method. The forty-two mutants obtained were fermented in koji extract medium and almost all of them produced more malate than the parental strain. In a small-scale sake brewing test, several of these mutants produced 2.3 to 6.7 times higher concentrations of malate and 1.5 to 2.1 times higher total acidity than the parental strain. However, these mutants exhibited neither resistance to cycloheximide nor sensitivity to dimethyl succinate, which are used as the phenotypes for isolation of high-malate-producing sake yeasts. The expression levels of the MDH and FUM1 genes in one mutant (M20), which produced the highest amount of malate among the mutants obtained, were analyzed by Northern hybridization. The transcriptional level of the FUM1 gene in strain M20 during sake brewing had a similar profile to that in strain K-701. However, the transcriptional level of the MDH2 gene in strain M20 for days 4 and 8 of malate formation during sake brewing was higher than that in strain K-701.
 ...
PMID:Isolation of high-malate-producing sake yeasts from low-maltose-assimilating mutants. 1623 23

Malate in sake (a Japanese alcoholic beverage) is an important component for taste that is produced by yeasts during alcoholic fermentation. To date, many researchers have developed methods for breeding high-malate-producing yeasts; however, genes responsible for the high-acidity phenotype are not known. We determined the mutated gene involved in high malate production in yeast, isolated as a sensitive mutant to dimethyl succinate. In the comparative whole genome analysis between high-malate-producing strain and its parent strain, one of the non-synonymous substitutions was identified in the VID24 gene. The mutation of VID24 resulted in enhancement of malate-productivity and sensitivity to dimethyl succinate. The mutation appeared to lead to a deficiency in Vid24p function. Furthermore, disruption of cytoplasmic malate dehydrogenase (Mdh2p) gene in the VID24 mutant inhibited the high-malate-producing phenotype. Vid24p is known as a component of the multisubunit ubiquitin ligase and participates in the degradation of gluconeogenic enzymes such as Mdh2p. We suggest that the enhancement of malate-productivity results from an accumulation of Mdh2p due to the loss of Vid24p function. These findings propose a novel mechanism for the regulation of organic acid production in yeast cells by the component of ubiquitin ligase, Vid24p.
...
PMID:Enhancement of malate-production and increase in sensitivity to dimethyl succinate by mutation of the VID24 gene in Saccharomyces cerevisiae. 2698 42

Saccharomyces cerevisiae produces organic acids such as succinate, acetate, and malate during alcoholic fermentation. Since malate contributes to the pleasant taste of sake (a Japanese alcoholic beverage), various methods for breeding high-malate-producing yeast strains have been developed. Here, a high-malate-producing yeast strain F-701H was isolated. This mutant was sensitive to dimethyl succinate (DMS) and harbored a nonsense mutation in the peroxin gene PEX22, which was identified as the cause of high malate production by comparative genome analysis. This mutation, which appeared to cause Pex22p dysfunction, was sufficient to confer increased malate productivity and DMS sensitivity to yeast cells. Next, we investigated the mechanism by which this mutation led to high malate production in yeast cells. Peroxins, such as Pex22p, maintain peroxisomal biogenesis. Analysis of 29 PEX disruptants revealed an increased malate production by deletion of the genes encoding peroxins responsible for importing proteins (containing peroxisomal targeting signal 1, PTS1) into the peroxisomal matrix, and those responsible for the assembly of peroxins themselves in the peroxisomal membrane. A defect in peroxisomal malate dehydrogenase (Mdh3p), harboring endogenous PTS1, inhibited the high malate-producing phenotype in the PEX22 mutant. Moreover, Mdh3p, which was normally sorted to the peroxisomal matrix, was potentially mislocalized to the cytosol in the PEX22 mutant. This suggested that an increase in malate production resulted from the mislocalization of Mdh3p from the peroxisome to the cytoplasm due to the loss of peroxin-mediated transportation. Thus, the present study revealed a novel mechanism for organic acid productions in yeast during sake brewing.
 ...
PMID:Mutation in the peroxin-coding gene PEX22 contributing to high malate production in Saccharomyces cerevisiae. 2891 52