Kiuchi K, Nishikimi M, Yagi K
Biochim Biophys Acta. 1980 Jul 3;630(3):330-7. doi: 10.1016/0304-4165(80)90281-0.
The effect of riboflavin deficiency on the activity of L-gulonolactone oxidase [L-gulono-gamma-lactone: oxygen 2-oxidoreductase, EC 1.1.3.8] and on vitamin C status was studied. A marked decrease in the specific activity of L-gulonolactone oxidase was observed in the liver microsomes isolated from riboflavin-deficient rats: the specific activity was approx. one-third of that in the microsomes isolated from control rats. The L-ascorbic acid content in the liver of the riboflavin-deficient rats was approx. one-half of that in the liver of the control rats. It seems that the rate of production of L-ascorbic acid in the riboflavin-deficient rats is limited by the decreased level of L-gulonolactone oxidase activity. Immunotitration using rabbit antiserum directed to L-gulonolactone oxidase revealed that a substantial amount of an inactive form of this enzyme is present in the liver microsomes of the riboflavin-deficient rats. L-Gulonolactone oxidase activity in the microsomes of these rats increased by approx. 35% upon addition of FAD, but it was slightly decreased by the addition of FMN or riboflavin. These results indicate that the liver microsomes of the riboflavin-deficient rats contain a protein which exhibits L-gulonolactone oxidase activity upon addition of Fad.
研究了核黄素缺乏对L-古洛糖酸内酯氧化酶[L-古洛糖酸-γ-内酯：氧2-氧化还原酶，EC 1.1.3.8]活性及维生素C状态的影响。在从核黄素缺乏大鼠分离的肝微粒体中，观察到L-古洛糖酸内酯氧化酶的比活性显著降低：其比活性约为从对照大鼠分离的微粒体中的三分之一。核黄素缺乏大鼠肝脏中的L-抗坏血酸含量约为对照大鼠肝脏中的一半。看来，核黄素缺乏大鼠中L-抗坏血酸的产生速率受到L-古洛糖酸内酯氧化酶活性降低水平的限制。使用针对L-古洛糖酸内酯氧化酶的兔抗血清进行免疫滴定显示，核黄素缺乏大鼠的肝微粒体中存在大量该酶的无活性形式。这些大鼠微粒体中的L-古洛糖酸内酯氧化酶活性在添加FAD后增加约35%，但添加FMN或核黄素后略有降低。这些结果表明，核黄素缺乏大鼠的肝微粒体含有一种蛋白质，添加Fad后该蛋白质表现出L-古洛糖酸内酯氧化酶活性。
