de Montigny J, Kern L, Hubert J C, Lacroute F
Laboratoire de génétique physiologique, I.B.M.C. du C.N.R.S., Strasbourg, France.
Curr Genet. 1990 Feb;17(2):105-11. doi: 10.1007/BF00312853.
Orotate phosphoribosyl transferase (OP-RTase) catalyses the transformation of orotate to OMP in the pyrimidine pathway. In the yeast Saccharomyces cerevisiae, the URA5 gene is known to encode this enzyme activity. In this paper we present the cloning and sequencing of a yeast gene, named URA10, encoding a second OPRTase enzyme. Comparison of the predicted amino acid sequences between URA5 and URA10 genes shows more than 75% similarity. These sequences have also been compared to those of Escherichia coli, Podospora anserina, Sordaria macrospora and Dictyostelium discoideum. Remarkable similarities in the primary structure of these proteins have been found. Gene disruption experiments revealed that URA10 gene expression is responsible for the leaky phenotype of a ura5 mutant. Assays of OPRTase activity in extracts from ura5 and ura10 mutants indicate that the URA10 product contributes only 20% of the total activity found in wild type cells.
乳清酸磷酸核糖基转移酶（OP-RTase）在嘧啶途径中催化乳清酸转化为乳清苷一磷酸（OMP）。在酿酒酵母中，已知URA5基因编码这种酶活性。在本文中，我们展示了一个名为URA10的酵母基因的克隆和测序，该基因编码第二种OPRTase酶。URA5和URA10基因预测氨基酸序列的比较显示出超过75%的相似性。这些序列也与大肠杆菌、鹅口疮疫霉、大孢粪壳菌和盘基网柄菌的序列进行了比较。已发现这些蛋白质一级结构存在显著相似性。基因破坏实验表明URA10基因表达导致ura5突变体的渗漏表型。ura5和ura10突变体提取物中OPRTase活性的测定表明，URA10产物仅占野生型细胞中总活性的20%。
