Herbert R A, Macfarlane G T
Arch Microbiol. 1980 Dec;128(2):233-8. doi: 10.1007/BF00406164.
Rhodopseudomonas acidophila strain 7050 achieved balance growth when provided with either asparagine or glutamine as nitrogen source. Under these growth conditions R. acidophila synthesized a mixed amidase which exhibited similar activity (223--422 nmol/min . mg protein) against either nitrogen source. Determination of the free intracellular amino acid pools show that deamidation of asparagine and glutamine resulted in elevated levels of both aspartate and glutamate. Cell-free extracts of R. acidophila showed significant aminotransferase activity, particularly glutamine-oxaloacetate aminotransferase (89.7--209.3 nmol/min . mg protein), glycine oxaloacetate aminotransferase (135--227 nmol/min . mg protein), alanine glyoxylate aminotransferase (66.3--163.2 nmol/min . mg protein) and serine-glyoxylate aminotransferase (57.1--68.4 nmol/min . mg protein). Short term labelling experiments using 14C-glyoxylate show that glycine plays an important role in amino nitrogen transfer in R. acidophila and that the enzymes for the metabolism of glyoxylate via glycine, serine and hydroxypyruvate were present in cell-free extracts. These data confirm that R. acidophila can satisfy all its' nitrogen requirements by transamination.
嗜酸红假单胞菌7050菌株在以天冬酰胺或谷氨酰胺作为氮源时能实现平衡生长。在这些生长条件下，嗜酸红假单胞菌合成了一种混合酰胺酶，该酶对任何一种氮源都表现出相似的活性（223 - 422纳摩尔/分钟·毫克蛋白质）。对细胞内游离氨基酸库的测定表明，天冬酰胺和谷氨酰胺的脱酰胺作用导致天冬氨酸和谷氨酸水平升高。嗜酸红假单胞菌的无细胞提取物显示出显著的转氨酶活性，尤其是谷氨酰胺 - 草酰乙酸转氨酶（89.7 - 209.3纳摩尔/分钟·毫克蛋白质）、甘氨酸草酰乙酸转氨酶（135 - 227纳摩尔/分钟·毫克蛋白质）、丙氨酸乙醛酸转氨酶（66.3 - 163.2纳摩尔/分钟·毫克蛋白质）和丝氨酸 - 乙醛酸转氨酶（57.1 - 68.4纳摩尔/分钟·毫克蛋白质）。使用¹⁴C - 乙醛酸进行的短期标记实验表明，甘氨酸在嗜酸红假单胞菌的氨基氮转移中起重要作用，并且通过甘氨酸、丝氨酸和羟基丙酮酸代谢乙醛酸的酶存在于无细胞提取物中。这些数据证实嗜酸红假单胞菌可以通过转氨作用满足其所有的氮需求。
