West T P
Olson Biochemistry Laboratories, Department of Chemistry and Biochemistry, South Dakota State University, Brookings 57007, USA.
Can J Microbiol. 1998 Nov;44(11):1106-9. doi: 10.1139/cjm-44-11-1106.
A reductive pathway of uracil catabolism was shown to be functioning in Escherichia coli B ATCC 11303 by virtue of thin-layer chromatographic and enzyme analyses. A mutant defective in uracil catabolism was isolated from this strain and subsequently characterized. The three enzyme activities associated with the reductive pathway of pyrimidine catabolism were detectable in the wild-type E. coli B cells, while the mutant strain was found to be deficient for dihydropyrimidine dehydrogenase activity. The dehydrogenase was shown to utilize NADPH as its nicotinamide cofactor. Growth of ATCC 11303 cells on uracil or glutamic acid instead of ammonium sulfate as a nitrogen source increased the reductive pathway enzyme activities. The mutant strain exhibited increased catabolic enzyme activities after growth on ammonium sulfate or glutamic acid.
通过薄层色谱分析和酶分析表明，尿嘧啶分解代谢的还原途径在大肠杆菌B ATCC 11303中发挥作用。从该菌株中分离出一株尿嘧啶分解代谢缺陷型突变体，并对其进行了后续表征。在野生型大肠杆菌B细胞中可检测到与嘧啶分解代谢还原途径相关的三种酶活性，而突变株被发现缺乏二氢嘧啶脱氢酶活性。该脱氢酶被证明利用NADPH作为其烟酰胺辅因子。以尿嘧啶或谷氨酸代替硫酸铵作为氮源时，ATCC 11303细胞的生长增加了还原途径酶的活性。突变株在以硫酸铵或谷氨酸为氮源生长后，分解代谢酶活性增加。
