与去唾液酸血清类黏蛋白偶联的谷氨酰胺酶在小鼠肝脏中的摄取动力学及活性

Kinetics of uptake and activity in mouse liver of glutaminase coupled to desialated orosomucoid.

作者信息

Schmer G, Holcenberg J S, Roberts J

出版信息

Biochim Biophys Acta. 1978 Feb 1;538(3):397-405. doi: 10.1016/0304-4165(78)90401-4.

Abstract

Desialised orosomucoid (alpha-1-acidic glycoprotein) was coupled to Pseudomonas 7A glutaminase-asparaginase by glutaraldehyde, iodinated and injected into mice. The half-life of radioactivity and glutaminase activity in plasma was about 7 min. Radioactivity and glutaminase activity in the liver reached a peak at about 20 min. The radioactivity in liver then declined with a half-life of about 20 min. Enzyme activity in liver declined with a half-life of about 10 min. The ratio of enzyme activity to radioactivity was lower in the liver than in plasma at all times during the experiment, indicating rapid hepatic inactivation of the enzyme. Uptake into the liver could be blocked by excess desialised orosomucoid. Glutamine levels in the liver were about 10% of normal for 44 min but returned to 50% of normal by 93 min. Intestines, kidney and spleen failed to exhibit any appreciable uptake of desialated orosomucoid glutaminase-asparaginase.

摘要

去唾液酸血清类黏蛋白（α-1-酸性糖蛋白）通过戊二醛与铜绿假单胞菌7A谷氨酰胺酶-天冬酰胺酶偶联，进行碘化后注射到小鼠体内。血浆中放射性和谷氨酰胺酶活性的半衰期约为7分钟。肝脏中的放射性和谷氨酰胺酶活性在约20分钟时达到峰值。随后肝脏中的放射性以约20分钟的半衰期下降。肝脏中的酶活性以约10分钟的半衰期下降。在实验期间的所有时间里，肝脏中酶活性与放射性的比值均低于血浆中的比值，表明该酶在肝脏中迅速失活。肝脏摄取可被过量的去唾液酸血清类黏蛋白阻断。肝脏中的谷氨酰胺水平在44分钟内约为正常水平的10%，但在93分钟时恢复到正常水平的50%。肠道、肾脏和脾脏未表现出去唾液酸化血清类黏蛋白谷氨酰胺酶-天冬酰胺酶的任何明显摄取。