Okuyama K, Hamamoto T, Noguchi T, Midorikawa Y
Research & Development Division, Yamasa Corporation, Chiba, Japan.
Biosci Biotechnol Biochem. 1996 Oct;60(10):1655-9. doi: 10.1271/bbb.60.1655.
The pyrimidine nucleoside phosphorylase (Py-NPase) of Bacillus stearothermophilus TH 6-2 is a dimer of 46-kDa subunits and catalyzes the reversible phosphorolysis of uridine and thymidine. The gene encoding this pyrimidine nucleoside phosphorylase (pyn gene) has been cloned and sequenced from B. stearothermophilus TH 6-2. The pyn gene corresponded to an open reading frame of 1299 nucleotides that translates into a putative 433 amino acid protein with a molecular weight of 46,271. The deduced amino terminal sequence of Py-NPase coincided with that previously found for the purified enzyme. The deduced amino acid sequence of Py-NPase shared significant similarity with those of human and Escherichia coli thymidine phosphorylases. The cloned pyn gene was overexpressed in E. coli cells to produce an active enzyme in large quantities that accounted for approximately 20% of the total protein.
嗜热脂肪芽孢杆菌TH 6-2的嘧啶核苷磷酸化酶（Py-NPase）是由46 kDa亚基组成的二聚体，催化尿苷和胸苷的可逆磷酸解反应。编码该嘧啶核苷磷酸化酶的基因（pyn基因）已从嗜热脂肪芽孢杆菌TH 6-2中克隆并测序。pyn基因对应于一个1299个核苷酸的开放阅读框，可翻译成一个推定的433个氨基酸的蛋白质，分子量为46271。推导的Py-NPase氨基末端序列与先前纯化酶的序列一致。Py-NPase的推导氨基酸序列与人和大肠杆菌胸苷磷酸化酶的序列具有显著相似性。克隆的pyn基因在大肠杆菌细胞中过表达，以大量产生一种活性酶，该酶约占总蛋白的20%。
