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標題: | 大豆苗中硝酸還原酵素—受質誘導合成,酵素純化及其性質 Nitrate Reductase of Soybean Seedings—Substrate Induction,Enzyme Purification and Properties |
作者: | Tai-Sen Soong 宋台生 |
出版年 : | 1974 |
學位: | 碩士 |
摘要: | 1.大豆苗經1 mM硝酸鈣誘導處理3小時後,硝酸還原酵素活性可達於最高。 2.大豆苗硝酸還原酵素,在標準測定情況下,其最適酸度是7.2;最適溫度是27℃。酵素對受質的Km是4.6×10-4M 3.粗酵素經硫胺沉澱法,磷酸鈣膠法及DEAE-cellulose gel法純化後,可獲17.2倍之純化效果,是遠較Schrader等(1968)所得100倍為小。其原因在繼續追究中。 4.適當濃度之有機含硝基化合物可誘導此酵素的新的合成,惟其誘導機構可能與無機硝酸鹽的誘導者不同。 5.在暗室中生長的大豆苗,Kinetin可刺激酵素的誘導合成作用;Indole-3-Acetic Acid及Gibberellic Acid無影響。光照下生長的大豆苗,外加之植物荷爾蒙時無影響。 Nitrate reductase (E.C. 1661) in soybean seedlings was partially purified and characterized. Its synthesis and/or activity by the effects of inorganic nitrate, organic nitro-compounds (chloramphenicol, N, N'-dinitroethylene diamide, -nitroaniline, 2,4-dinitrophenol) and plant hormones have been studied. By means of ammonia sulfate fractionations, calcium phosphate gel batch, and DEAE-cellulose gel batch, the nitrate reductase has been purified about 17-fold. Under the standard assay conditions, the enzyme has optimum pH at 7.2 and optimum temperature at 27 C. Its apparent Km value for nitrate is 4,6 × 10-4 M. Exogeneously applied organic nitro-compounds, as inorganic itrate, show approximately the same extent of induction of trate reductase synthesis. Because of their additive effects the induction of nitrate reductase synthesis, the action Lechanisms of organic nitro-compounds and inorganic nitrate may be somehow different. Kinetin apparently stimulates the substrate induction of nitrate reductase in dark grown soybean seedlings, but Gibberellic acid and Indole-3-acetic acid do not. Furthermore, the effect of kinetin could be significantly evident within 3 hours after application. The possible physiological role of kinetin stimulation is discussed. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/75768 |
全文授權: | 未授權 |
顯示於系所單位: | 植物科學研究所 |
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