Intracellular substrates of a heme-containing ascorbate oxidase in Pleurotus ostreatus.
A novel heme-containing ascorbate oxidase isolated from oyster mushroom, Pleurotus ostreatus, catalyzes oxidation of ascorbic acid (Kim et al., 1996). In this report, we describe the identification of intracellular substrates of the enzyme in the mushroom. Six compounds, which can serve as substrate of the heme-containing ascorbate oxidase, were identified as L-ascorbic acid, D-erythroascorbic acid, 5-O-(alpha-D-glucopyranosyl)-D-erythroascorbic acid, 5-O-(alpha-D-xylopyranosyl)-D-erythroascorbic acid, 5-methyl-5-O-(alpha-D-gluco-pyranosyl)-D-erythroascorbic acid, and 5-methyl-5-O-(alpha-D-xylopyranosyl)-D-erythroascorbic acid. All of the compounds were oxidized at a significant rate by the heme-containing ascorbate oxidase. Oxidation of the compounds produced equimolar amounts of hydrogen peroxide per mole of substrate.
Lee
Seung-Rock
SR
Department of Biochemistry, Chonnam National University Medical School, Gwangju, 501-190, Republic of Korea. leesr@chornam.ac.kr
Joo
Woo-Jeong
WJ
Baek
Yong-Un
YU
Lee
Youn-Kyong
YK
Yu
Seong-Woon
SW
Kim
Yeon-Ran
YR
Chay
Kee-Oh
KO
Cho
Seung-Hyun
SH
Kang
Sa-Ouk
SO
Rang
Sa-Ouk
SO
D001204:Ascorbate Oxidase / Q000737:chemistry* / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry* / Q000378:metabolism; D006418:Heme / Q000378:metabolism*; D010084:Oxidation-Reduction; D020076:Pleurotus / Q000737:chemistry / Q000201:enzymology*; D013379:Substrate Specificity
D005656:Fungal Proteins; D006418:Heme; D001204:Ascorbate Oxidase