Taylor
, W. H. (Portland State College, Portland, Ore.), M. L.
Taylor, and D. F. Eames
. Two functionally different dihydroorotic dehydrogenases in bacteria. J. Bacteriol.
91:
2251–2256. 1966.—We have investigated the relationship between the two kinds of dihydroorotic dehydrogenases produced by bacteria. A pseudomonad, capable of growth on a salts medium with glucose, aspartate, glycerol, or orotate as the carbon source, was isolated from lake bank mud. A particle-bound dihydroorotic dehydrogenase, similar to the biosynthetic enzyme in
Escherichia coli
, was formed by the pseudomonad when the carbon source was orotate, glucose, glycerol, or aspartate. A soluble, degradative nicotinamide adenine dinucleotide phosphate-linked dihydroorotic dehydrogenase, as well as the particle-bound biosynthetic enzyme, was formed when the pseudomonad was cultivated on orotate. The biosynthetic enzyme links to oxygen or ferricyanide, but not to pyridine nucleotides.
Zymobacterium oroticum
, when cultivated on glucose, contained only the biosynthetic type of dihydroorotic dehydrogenase. The presence of two functionally different dihydroorotic dehydrogenases in the pseudomonad was suggested on the basis of the following observations: (i) the two enzyme activities were separated by centrifugation; (ii) the pyridine nucleotide-linked activity was formed only when orotate was present in the growth medium; and (iii) the biosynthetic enzyme was stable to storage at −20 C for 4 months, whereas the degradative enzyme activity was destroyed by storage under these conditions.
泰勒(Taylor),W.H.(俄勒冈州波特兰州州立学院),M.L.泰勒和D.F.伊姆斯(Eames)。细菌中两种功能不同的双氢乳酸脱氢酶。《细菌学杂志》91:2251-2256。1966年。——我们研究了细菌所产生的两种双氢乳酸脱氢酶之间的关系。从湖岸泥土中分离出一种假单胞菌,能够在含有葡萄糖、天冬氨酸、甘油或乳酸盐作为碳源的盐基培养基上生长。当碳源为乳酸盐、葡萄糖、甘油或天冬氨酸时,该假单胞菌形成了一种类似于大肠杆菌中生物合成酶的粒子结合型双氢乳酸脱氢酶。当该假单胞菌在乳酸盐上培养时,形成可溶性的、降解性的烟酰胺腺嘌呤二核苷酸磷酸型双氢乳酸脱氢酶,以及粒子结合型的生物合成酶。生物合成酶与氧或铁氰化物结合,但不与吡啶核苷酸结合。当以葡萄糖培养的嗜酸性乳酸杆菌中,只含有生物合成型的双氢乳酸脱氢酶。基于以下观察结果,建议在假单胞菌中存在两种功能不同的双氢乳酸脱氢酶:(i)通过离心分离了两种酶活性;(ii)只有在生长基质中存在乳酸盐时,才形成吡啶核苷酸连接的酶活性;(iii)生物合成酶在-20℃下储存4个月后仍稳定,而降解酶活性在这些条件下被破坏。