Bjelaković G, Milenović D, Zivić R, Nikolić J, Kostić G, Bjelković B
Institute of Biochemistry, School of Medicine, Nish.
Srp Arh Celok Lek. 1998 May-Jun;126(5-6):153-6.
Arginase (EC 3.5.3.1) is one of the essential enzymes in the terminal stages of the urea cycle in the liver which participates in the elimination of ammonia from the human body [1, 7]. Except in liver tissue arginase is also present in many human tissues and in the circulating blood cells, especially in erythrocytes and leukocytes. Arginase splits arginase to urea and ornithine that serve for biosynthesis of amino acid proline, glutamic acid and biosynthesis of polyamines-spermine, spermidine and putrescine. Arginase activity is high during the mitotic cycle, with the function in phase S of the cell cycle. The aim of our study was to assess the arginase activity in the blood of children with some haematologic diseases.
We examined the arginase activity in blood plasma and erythrocytes of children who suffer from some haematological disorders (27 patients) and in healthy children (control group-15 subjects). The enzyme activity was measured with spectrophotometric method on the basis of the determination of the amount of liberated ornithine from substrate-arginine [3].
The obtained results suggest that arginase activity was much higher in the blood of ill children (Table 1 and Figure 1). In the control group of children (total 15) plasma arginase activity was in the range of 0 to 20 U/L x = 0.86 U/L), and enzyme activity in erythrocytes was 1.62-3.98 U/g Hb (x = 2.81 U/g Hb). Erythrocytes enzyme activity and plasma enzyme activity were in ranges of 4.03-5.26 U/L with the mean value of x = 4.56 U/L, and arginase activity in erythrocytes was in ranges of 9.38-14.16 U/g Hb, with mean value x = 11.34 U/g Hb, respectively. Arginase activity in erythrocytes was also significantly higher in children with non-spherocytic haemolytic anaemia (9 children) and was in ranges of 5.33-9.58 U/g Hb (x = 7.29 U/g Hb), with the relatively low values in plasma, 0-4.14 U/L (x = 1.75 U/L). In children with sideropenic anaemia (total number-11) arginase activity in erythrocytes was also very significantly increased with the range between 2.86 and 14.16 U/g Hb (x = 5.54 U/g Hb) while the plasma enzyme activity was relatively low, with the values in range of 0-4.98 U/L (x = 1.41 U/L); in myelodysplastic syndrome (4 pts) arginase activity in plasma was very low (0-0.71 U/L; x = 0.26 U/L) with higher values of arginase activity in erythrocytes (4.22-5.89 U/g Hb; x = 4.94 U/g Hb).
We have concluded that the enzyme activity was the highest in erythrocyte haemolysates of patients with spherocytosis, non-sherocytic haemolytic anaemia; it was also high, but in a smaller degree, in erythrocytes of children with sideropenic anaemia and myelodysplastic syndrome; arginase activity in plasma of these children was higher in comparison with enzyme activity in plasma and erythrocytes of healthy children. Our results are in agreement with data from literature where it is stated that the younger erythrocytes have the highest arginase activity than the mature erythrocytes [4].
The measurement of arginase activity in plasma and erythrocytes is a good diagnostic indicator for the presence of young erythrocytes and reticulocytes in the circulating blood as is the good sign for the detection of haemolytic processes.
精氨酸酶（EC 3.5.3.1）是肝脏尿素循环终末阶段的关键酶之一，参与人体氨的清除[1,7]。除肝脏组织外，精氨酸酶也存在于许多人体组织及循环血细胞中，尤其是红细胞和白细胞。精氨酸酶将精氨酸分解为尿素和鸟氨酸，用于氨基酸脯氨酸、谷氨酸的生物合成以及多胺（精胺、亚精胺和腐胺）的生物合成。精氨酸酶活性在有丝分裂周期中较高，在细胞周期的S期发挥作用。我们研究的目的是评估患有某些血液系统疾病儿童血液中的精氨酸酶活性。
我们检测了患有某些血液系统疾病的儿童（27例患者）及健康儿童（对照组 - 15名受试者）血浆和红细胞中的精氨酸酶活性。基于从底物精氨酸中释放的鸟氨酸量的测定，采用分光光度法测量酶活性[3]。
所得结果表明，患病儿童血液中的精氨酸酶活性高得多（表1和图1）。在儿童对照组（共15名）中，血浆精氨酸酶活性范围为0至20 U/L（x = 0.86 U/L），红细胞中的酶活性为1.62 - 3.98 U/g Hb（x = 2.81 U/g Hb）。患病儿童红细胞酶活性和血浆酶活性范围分别为4.03 - 5.26 U/L，平均值x = 4.56 U/L，红细胞中的精氨酸酶活性范围为9.38 - 14.16 U/g Hb，平均值x = 11.34 U/g Hb。非球形细胞溶血性贫血患儿（9例）红细胞中的精氨酸酶活性也显著更高，范围为5.33 - 9.58 U/g Hb（x = 7.29 U/g Hb），血浆中值相对较低，为0 - 4.14 U/L（x = 1.75 U/L）。缺铁性贫血患儿（共11例）红细胞中的精氨酸酶活性也非常显著升高，范围在2.86至14.16 U/g Hb之间（x = 5.54 U/g Hb），而血浆酶活性相对较低，值在0 - 4.98 U/L范围（x = 1.41 U/L）；骨髓增生异常综合征患儿（4例）血浆中的精氨酸酶活性非常低（0 - 0.71 U/L；x = 0.26 U/L），红细胞中的精氨酸酶活性较高（4.22 - 5.89 U/g Hb；x = 4.94 U/g Hb）。
我们得出结论，球形红细胞增多症、非球形细胞溶血性贫血患者红细胞溶血产物中的酶活性最高；缺铁性贫血和骨髓增生异常综合征患儿红细胞中的酶活性也较高，但程度较小；这些患儿血浆中的精氨酸酶活性相较于健康儿童血浆和红细胞中的酶活性更高。我们的结果与文献数据一致，文献表明年轻红细胞的精氨酸酶活性高于成熟红细胞[4]。
血浆和红细胞中精氨酸酶活性的测量是循环血液中存在年轻红细胞和网织红细胞的良好诊断指标，也是检测溶血过程的良好迹象。
