Occurrence of a NADH-dependent methylglyoxal reducing system: Conversion of methylglyoxal to acetol by aldehyde reductase from Hansenula mrakii

Inoue, Yoshiharu; Ikemoto, Shigeaki; Kitamura, Koji; Kimura, Akira

doi:10.1016/0922-338x(92)90266-w

Cited by 8 publications

(3 citation statements)

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“…Methylglyoxal is reduced to the l-lactaldehyde by NADPH-dependent methylglyoxal reductase [15], after which the l-lactaldehyde is oxidized to l-lactic acid by NAD + -dependent lactaldehyde dehydrogenase [16], of which the activity is linked with NAD(P)H dehydrogenase [17]. In the yeast Hansenula mrakii, methylglyoxal is reduced to acetol by aldehyde reductase and the enzyme partially purified, although this enzyme activity has not been found in S. cerevisiae [18].…”

Section: Degradation Pathway Of Methylglyoxalmentioning

confidence: 96%

Glyoxalase system in yeasts: Structure, function, and physiology

Inoue¹,

Maeta²,

Nomura³

2011

Seminars in Cell & Developmental Biology

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The glyoxalase system consists of glyoxalase I and glyoxalase II. Glyoxalase I catalyzes the conversion of methylglyoxal (CH(3)COCHO), a metabolite derived from glycolysis, with glutathione to S-D-lactoylglutathione, while glyoxalase II hydrolyses this glutathione thiolester to D-lactic acid and glutathione. Since methylglyoxal is toxic due to its high reactivity, the glyoxalase system is crucial to warrant the efficient metabolic flux of this reactive aldehyde. The budding yeast Saccharomyces cerevisiae has the sole gene (GLO1) encoding the structural gene for glyoxalase I. Meanwhile, this yeast has two isoforms of glyoxalase II encoded by GLO2 and GLO4. The expression of GLO1 is regulated by Hog1 mitogen-activated protein kinase and Msn2/Msn4 transcription factors under highly osmotic stress conditions. The physiological significance of GLO1 expression in response to osmotic stress is to combat the increase in the levels of methylglyoxal in cells during the production of glycerol as a compatible osmolyte. Deficiency in GLO1 in S. cerevisiae causes pleiotropic phenotypes in terms of stress response, because the steady state level of methylglyoxal increases in glo1Δ cells thereby constitutively activating Yap1 transcription factor. Yap1 is crucial for oxidative stress response, although methylglyoxal per se does not enhance the intracellular oxidation level in yeast, but it directly modifies cysteine residues of Yap1 that are critical for the nucleocytoplasmic localization of this b-ZIP transcription factor. Consequently, glyoxalase I can be defined as a negative regulator of Yap1 through modulating the intracellular methylglyoxal level.

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Section: Degradation Pathway Of Methylglyoxalmentioning

confidence: 96%

Glyoxalase system in yeasts: Structure, function, and physiology

Inoue¹,

Maeta²,

Nomura³

2011

Seminars in Cell & Developmental Biology

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“…In some microorganisms, methylglyoxal is directly oxidized to pyruvic acid by 2-oxoaldehyde dehydrogenase (methylglyoxal dehydrogenase) (15)(16)(17)(18). Methylglyoxal was also reduced to acetol by aldehyde reductase, and the enzyme was partially purified from a yeast, Hansenula mrakii IFO 0895 (19).…”

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confidence: 99%

Identification of the Structural Gene for Glyoxalase I from Saccharomyces cerevisiae

Inoue

Kimura

1996

Journal of Biological Chemistry

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The structural gene for glyoxalase I (GLO1) of Saccharomyces cerevisiae was identified. The GLO1 gene contained an open reading frame with 326 amino acids, and the molecular weight of the gene product (Glo1p) deduced from the DNA sequence was calculated to be 37,207.06. Glyoxalase I activity increased approximately 95-fold when the GLO1 gene was introduced into the yeast cell with a multicopy plasmid, and the resultant transformant showed the increased resistance against methylglyoxal. Since the knockout mutant of the GLO1 gene of haploid strain of S. cerevisiae was still viable, the GLO1 gene was thought to be unnecessary for growth of the yeast. The GLO1 gene was overexpressed in two kinds of glutathione-deficient mutants, ␥-glutamylcysteine synthetase-deficient (gsh1 ؊) and glutathione synthetase-deficient (gsh2 ؊), respectively, and the sensitivites to methylglyoxal were compared. The gsh1-deficient mutant, which could not produce glutathione at all, was hypersensitive to methylglyoxal, and overproduction of the Glo1p did not restore the growth arrest caused by exogenously added methylglyoxal. The gsh2-deficient mutant, which accumulates ␥-glutamylcysteine (an intermediate of glutathione biosynthesis), was also sensitive to methylglyoxal compared with the isogenic wild type strain, although the growth arrest caused by methylglyoxal was partially restored by overexpression of the GLO1 gene. Purified glyoxalase I from yeast could use ␥-glutamylcysteine as a substrate (k cat /K m ‫؍‬ 1.89 ؋ 10 7 M ؊1 s ؊1 , glutathione; 3.47 ؋ 10 4 M ؊1 s ؊1 , ␥-glutamylcysteine).

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“…This route is found in a bacterium, Pseudomonus putida. (4) Reduction to acetol in which methylglyoxal is reduced to acetol (1-hydroxy-2-propanone) by NADH-dependent aldehyde reductase [9]. This route was found recently in the yeast Hunsenulu mrakii.…”

mentioning

confidence: 98%