SOME PROPERTIES OF SULFITE REDUCTASE FROM YEAST
スポンサーリンク
概要
- 論文の詳細を見る
The MVH- and NADPH-linked sulfite reducing activities were assayed in extracts obtained from a wild strain of Saccharomyces cerevisiae and various auxotrophic mutants derived from it. All the ex-tracts possessing the NADPH-1inked activity also showed the MVH-linked activity, and all those lacking the latter also lacked the former. However, extracts from several mutants had the MVH-linked activity without having the other. NADPH-sulfite reductase was purified nearly 200-fold from extracts of the wild strain. Throughout the purification steps, the MVH-linked activity was also purified in association with the NADPH-linked activity, and the ratio between the two remained essentially constant. However, on exposure to heat, low ionic strengths and PCMB, only the NADPH-linked activity was lost, leaving the MVH-linked activity almost unaffected. Both activities were sensitive to cyanide. The sulfite reductase could also reduce nitrite and hydroxylamine, and the nitrite- and hydroxylamine-reducing activity was sensitive to the treatments which inhibited the NADPH-sulfite reducing activity. Addition of nitrite or hydroxylamine competitively inhibits the NADPH-linked sulfite reduction. The enzyme also showed diaphorase activity, reducing DPIP or MV. This activity was inhibited by the treatments to which the NADPH-linked sulfite reduction was sensitive, but it was not sensitive to cyanide. A tentative schematic model for yeast sulfite reductase is presented.
- 日本植物生理学会の論文