Calder K, Burke K A, Lascelles J
Arch Microbiol. 1980 Jun;126(2):149-53. doi: 10.1007/BF00511220.
An experimental system has been devised for induction of nitrate reductase in suspensions of wild type Paracoccus denitrificans incubated with limited aeration in the presence of azide, nitrate or nitrite. Azide promoted maximum synthesis of enzyme, accompanied by formation of excess b-type cytochrome; the level of enzyme attained with nitrate was less and c-type cytochrome predominated in the membrane. The nitrate reductase was solubilized with deoxycholate from membranes of azide-induced cells and was identified as a major polypeptide Mr = 150,000 by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Mutants strains lacking nitrate reductase activity were isolated on the basis of resistance to chlorate and mutant M-1 was examined in detail. When incubated in the cell suspension system M-1 formed a membrance protein Mr = 150,000 similar to that attributed to nitrate reductase in the wild type. Maximum formation of the protein by M-1 occurred without inducer and it was accompanied by synthesis of excess b-type cytochrome. The observations with wild type and M-1 indicate that nitrate reductase protein and b-type cytochrome are co-regulated and that the active enzyme has a role in regulating its own synthesis.
已设计出一种实验系统，用于在叠氮化物、硝酸盐或亚硝酸盐存在下，对限气培养的野生型反硝化副球菌悬浮液诱导硝酸盐还原酶。叠氮化物促进了酶的最大合成，并伴有过量b型细胞色素的形成；硝酸盐诱导的酶水平较低，且c型细胞色素在膜中占主导地位。用脱氧胆酸盐从叠氮化物诱导细胞的膜中溶解硝酸盐还原酶，并通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳鉴定为主要多肽，分子量为150,000。基于对氯酸盐的抗性分离出缺乏硝酸盐还原酶活性的突变菌株，并对突变体M-1进行了详细研究。当在细胞悬浮系统中培养时，M-1形成了一种分子量为150,000的膜蛋白，类似于野生型中归因于硝酸盐还原酶的蛋白。M-1在没有诱导剂的情况下该蛋白形成量最大，并且伴有过量b型细胞色素的合成。对野生型和M-1的观察表明，硝酸盐还原酶蛋白和b型细胞色素是共同调节的，并且活性酶在调节其自身合成中起作用。
