Regulation of intracellular formaldehyde toxicity during methanol metabolism of the methylotrophic yeast Pichia methanolica.
In this study we found that the methylotrophic yeast Pichia methanolica showed impaired growth on high methanol medium (>5%, or 1.56 M, methanol). In contrast, P. methanolica grew well on glucose medium containing 5% methanol, but the growth defects reappeared on glucose medium supplemented with 5 mM formaldehyde. During methanol growth of P. methanolica, formaldehyde accumulated in the medium up to 0.3 mM before it was consumed rapidly based on cell growth. These findings indicate that the growth defect of P. methanolica on high methanol media is not caused directly by methanol toxicity, but rather by formaldehyde, which is a key toxic intermediate of methanol metabolism. Moreover, during methanol growth of P. methanolica, expression of enzymes in the methanol-oxidation pathway were induced before the alcohol oxidase isozymes Mod1p and Mod2p, and Mod1p expression was induced before Mod2p. These results suggest that to avoid excess accumulation of formaldehyde-the toxic intermediate of methanol metabolism-P. methanolica grown on methanol strictly regulates the order in which methanol-metabolizing enzymes are expressed.
Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
Keishi
K
Wakayama
Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
Sakiko
S
Yamaguchi
Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
Akihito
A
Takeuchi
Department of Food Science and Technology, Faculty of Bioindustry, Tokyo University of Agriculture, 196 Yasaka, Abashiri, Hokkaido 099-2493, Japan.
Tasuku
T
Mizumura
Department of Food Science and Technology, Faculty of Bioindustry, Tokyo University of Agriculture, 196 Yasaka, Abashiri, Hokkaido 099-2493, Japan.
Shotaro
S
Ozawa
Department of Food Science and Technology, Faculty of Bioindustry, Tokyo University of Agriculture, 196 Yasaka, Abashiri, Hokkaido 099-2493, Japan.
Noboru
N
Tomizuka
Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
Takashi
T
Hayakawa
Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan. Electronic address: t_nakaga@gifu-u.ac.jp.
Tomoyuki
T
Nakagawa
D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D019610:Cytoprotection / Q000235:genetics; D005557:Formaldehyde / Q000378:metabolism* / Q000633:toxicity*; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D053858:Metabolic Networks and Pathways / Q000187:drug effects / Q000235:genetics; D000432:Methanol / Q000378:metabolism* / Q000633:toxicity; D010843:Pichia / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism
D005557:Formaldehyde; D000429:Alcohol Oxidoreductases; C019643:alcohol oxidase; D000432:Methanol
Alcohol oxidase isozymes; Formaldehyde; Methanol metabolic enzymes; Methylotrophic yeast; Pichia methanolica