Morris S M, Bhamidipati D, Kepka-Lenhart D
Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, PA 15261, USA.
Gene. 1997 Jul 9;193(2):157-61. doi: 10.1016/s0378-1119(97)00099-1.
A full-length cDNA encoding type II arginase was isolated from a human kidney cDNA library and its sequence compared to those of vertebrate type I arginases as well as to arginases of bacteria, fungi and plants. The predicted sequence of human type II arginase is 58% identical to the sequence of human type I arginase but is 71% identical to the sequence of Xenopus type II arginase, suggesting that duplication of the arginase gene occurred before mammals and amphibians diverged. Seven residues known to be essential for activity were found to be conserved in all arginases. Type II arginase mRNA was detected in virtually all human and mouse RNA samples tested whereas type I arginase mRNA was found only in liver. At least five mRNA species hybridizing to type II arginase cDNA were found in the human RNA samples whereas only a single type II arginase mRNA species was found in the mouse. This raises the possibility that the multiple type II arginase mRNAs in humans arise from differential RNA processing or usage of alternative promoters.
从人肾cDNA文库中分离出编码II型精氨酸酶的全长cDNA，并将其序列与脊椎动物I型精氨酸酶以及细菌、真菌和植物的精氨酸酶序列进行比较。预测的人II型精氨酸酶序列与人类I型精氨酸酶序列的同一性为58%，但与非洲爪蟾II型精氨酸酶序列的同一性为71%，这表明精氨酸酶基因的复制发生在哺乳动物和两栖动物分化之前。发现所有精氨酸酶中七个已知对活性至关重要的残基是保守的。在几乎所有测试的人及小鼠RNA样本中均检测到II型精氨酸酶mRNA，而I型精氨酸酶mRNA仅在肝脏中发现。在人RNA样本中发现至少五种与II型精氨酸酶cDNA杂交的mRNA种类，而在小鼠中仅发现单一的II型精氨酸酶mRNA种类。这增加了人类中多种II型精氨酸酶mRNA源自RNA加工差异或使用替代启动子的可能性。
