Molchan O K, Dmitrieva N A, Romanova D V, Lopes L E, Debabov V G, Mironov A S
Institute of Genetics and Selection of Industrial Microorganisms, 1-yi Dorozhnyi proezd 1, Moscow, 113545 Russia.
Biochemistry (Mosc). 1998 Feb;63(2):195-9.
The structural udp gene encoding uridine phosphorylase (UPase) was cloned from the Salmonella typhimurium chromosome and overexpressed in E. coli cells. The S. typhimurium UPase was purified to an apparently homogeneous state, and some physicochemical characteristics of the enzyme were studied. The molecular weight of one subunit of UPase is 27.5 kD, and the optimal pH for its activity is 7.2--7.4. The native S. typhimurium UPase consists of six identical subunits, and its molecular weight is about 165 kD. According to these parameters, the S. typhimurium UPase is similar to the E. coli UPase. However, these enzymes differ substantially from one another by the substrate sensitivity and sensitivity to polarity of the medium. The S. typhimurium UPase has much higher phosphorylation activity toward thymidine, deoxyuridine, and 5;-bromide- or 5;-fluoride-containing analogs of nucleosides than that of E. coli UPase.
编码尿苷磷酸化酶（UPase）的结构udp基因从鼠伤寒沙门氏菌染色体中克隆出来，并在大肠杆菌细胞中过表达。鼠伤寒沙门氏菌UPase被纯化至表观均一状态，并对该酶的一些理化特性进行了研究。UPase一个亚基的分子量为27.5 kD，其活性的最适pH为7.2 - 7.4。天然的鼠伤寒沙门氏菌UPase由六个相同的亚基组成，其分子量约为165 kD。根据这些参数，鼠伤寒沙门氏菌UPase与大肠杆菌UPase相似。然而，这些酶在底物敏感性和对介质极性的敏感性方面存在很大差异。鼠伤寒沙门氏菌UPase对胸苷、脱氧尿苷以及含5'-溴或5'-氟的核苷类似物的磷酸化活性比大肠杆菌UPase高得多。
