Aminlari M
Department of Biochemistry, School of Veterinary Medicine, Shiraz University, Iran.
Clin Biochem. 1992 Dec;25(6):431-6. doi: 10.1016/0009-9120(92)90060-6.
Arginase catalyzes the conversion of arginine to urea and ornithine in the liver of ureotelic animals. Higher activity of this enzyme is found in tumors as well as in the sera of patients with hepatic diseases. We have developed a simple colorimetric method for its determination. This is based on the determination of residual arginine, after its conversion with p-nitrophenyl glyoxal (PNPG) at pH 9.0 in the presence of sodium ascorbate. The reaction product obeys Beer's law in the range of 0.01-0.20 mmol/L arginine with an arginine-equivalent molar extinction coefficient of 0.65 x 10(4) M-1 cm-1. The decrease in absorbance in the presence of arginase correlates with the enzyme activity. Color development as well as termination of enzyme activity is achieved by addition of a single reagent, thereby obviating the use of many chemicals necessary in other methods. The sensitivity of this method is equivalent to those of currently available procedures but has the added advantages of greater convenience.
在排尿素动物的肝脏中，精氨酸酶催化精氨酸转化为尿素和鸟氨酸。在肿瘤以及肝病患者的血清中发现该酶的活性较高。我们已经开发出一种简单的比色法来测定它。该方法基于在pH 9.0、抗坏血酸钠存在的条件下，精氨酸与对硝基苯乙二醛（PNPG）反应后，对剩余精氨酸的测定。反应产物在精氨酸浓度为0.01 - 0.20 mmol/L范围内符合比尔定律，精氨酸等效摩尔消光系数为0.65×10⁴ M⁻¹ cm⁻¹。在精氨酸酶存在的情况下吸光度的降低与酶活性相关。通过添加单一试剂即可实现显色以及酶活性的终止，从而避免了其他方法中所需的许多化学试剂的使用。该方法的灵敏度与目前可用的方法相当，但具有更方便的额外优点。
