黄嘌呤氧化酶的化学性质。与碘乙酰胺的反应。
The chemistry of xanthine oxidase. Reaction with iodoacetamide.
作者信息
Bray R C, Watts D C
出版信息
Biochem J. 1966 Jan;98(1):142-8. doi: 10.1042/bj0980142.
Abstract
- The reaction of milk xanthine oxidase with iodoacetamide has been studied with the silver-silver iodide electrode. 2. The reaction proceeds considerably faster in the presence of xanthine than in its absence. Anaerobically, with excess of xanthine, the reaction takes place as a rapid phase in which the enzyme is inactivated and in which approx. 1 thiol group/mol. of enzyme reacts and as a slower phase in which about 12 groups/mol. react. 3. The rapid reaction appears to be first-order with respect to xanthine oxidase and iodoacetamide and independent of the xanthine concentration with more than about 3mol. of xanthine/mol. of enzyme. 4. The velocity constant of the rapid phase is 0.26min.(-1) at 25 degrees and pH7.0, with 1mm-iodoacetamide and 17mum-xanthine oxidase. The velocity constant for the slower phase is about one-hundredth of this value. 5. The velocities of both phases increase with increasing pH in the range 5.0-9.6. 6. Xanthine may be replaced by salicylaldehyde without affecting the rate of loss of enzymic activity. With sodium dithionite as reducing agent, the reaction is slightly faster. 7. The possible function of thiol groups in the reaction mechanism of the enzyme is discussed.
摘要
- 已用银 - 碘化银电极研究了牛奶黄嘌呤氧化酶与碘乙酰胺的反应。2. 该反应在有黄嘌呤存在时比无黄嘌呤时进行得快得多。在厌氧条件下，有过量黄嘌呤时，反应分为快速阶段和缓慢阶段。快速阶段中酶失活，大约每摩尔酶有1个巯基反应；缓慢阶段中大约每摩尔酶有12个基团反应。3. 快速反应对于黄嘌呤氧化酶和碘乙酰胺似乎是一级反应，并且当黄嘌呤浓度超过每摩尔酶约3摩尔时，与黄嘌呤浓度无关。4. 在25℃和pH7.0条件下，对于1mM碘乙酰胺和17μM黄嘌呤氧化酶，快速阶段的速度常数为0.26min⁻¹。缓慢阶段的速度常数约为此值的百分之一。5. 在5.0 - 9.6范围内，两个阶段的速度都随pH升高而增加。6. 水杨醛可以替代黄嘌呤而不影响酶活性丧失的速率。以连二亚硫酸钠作为还原剂时，反应稍快一些。7. 讨论了巯基在该酶反应机制中的可能作用。
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3
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