大鼠肾脏碱性磷酸酶调节的分子机制
Molecular aspects of the regulation of rat kidney alkaline phosphatase.
作者信息
Melani F, Farnararo M, Chiarugi V P
出版信息
Biochem J. 1971 Jan;121(1):33-40. doi: 10.1042/bj1210033.
The mechanisms by which phosphate regulates the activity of alkaline phosphatase (orthophosphoric monoester phosphohydrolase, EC 3.1.3.1) in rat kidney were investigated. Measurements of incorporation of [(14)C]leucine into kidney alkaline phosphatase in rats fed on complete or phosphate-free diet provide evidence of a twofold increase in the rate of synthesis of the enzyme in diet-treated animals. Cycloheximide experiments indicated that control and diet-adapted enzyme decreases in activity according to first-order kinetics with a calculated half-life of 10.3 and 6.5h after complete and phosphate-free diet administration respectively. Basal and diet-adapted enzymes exhibit similar K(m) values for several phosphomonoesters and an identical degree of inhibition is produced by cysteine. In addition, the enzyme from both sources is the same with regard to heat inactivation at 45, 56 or 64 degrees C, to the profile of elution from Sephadex and to electrophoretic properties on polyacrylamide gel. A failure of rat kidney alkaline phosphatase to respond to cortisol (hydrocortisone) was also observed.
研究了磷酸盐调节大鼠肾脏中碱性磷酸酶（正磷酸单酯磷酸水解酶，EC 3.1.3.1）活性的机制。对喂食完全饲料或无磷饲料的大鼠肾脏碱性磷酸酶中[（14）C]亮氨酸掺入量的测量结果表明，经饮食处理的动物中该酶的合成速率提高了两倍。环己酰亚胺实验表明，对照酶和适应饮食的酶的活性根据一级动力学下降，在分别给予完全饲料和无磷饲料后，计算出的半衰期分别为10.3小时和6.5小时。基础酶和适应饮食的酶对几种磷酸单酯表现出相似的K（m）值，并且半胱氨酸产生的抑制程度相同。此外，来自这两种来源的酶在45、56或64℃下的热失活、从葡聚糖凝胶的洗脱曲线以及在聚丙烯酰胺凝胶上的电泳性质方面是相同的。还观察到大鼠肾脏碱性磷酸酶对皮质醇（氢化可的松）无反应。
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