Kiesow L A, Lindsley B F, Bless J W
J Bacteriol. 1977 Apr;130(1):20-5. doi: 10.1128/jb.130.1.20-25.1977.
CO2 fixation by particle-free extracts from Nitrobacter winogradskyi increased by addition of reduced nicotinamide adenine dinucleotide (NADH). Ribulose-1,5-diphosphate, however, increased CO2 fixation, even in the absence of NADH. Phosphoribulokinase (EC 2.7.1.19) was the enzyme of Nitrobacter extracts that was activated specifically by NADH. Pyridoxal-5-phosphate inhibited both CO2 fixation and NADH-activated phosphoribulokinase from Nitrobacter. However, it did not affect phosphoribulokinase from spinach leaves. Since the spinach enzyme had also no requirement for reduced pyridine nucleotides, it appears that pyridoxal phosphate interferes only with the binding of NADH and not with the binding of ribulose-5-phosphate and adenosine-5'-triphosphate. The regulation of phosphoribulokinase activity by NADH provided Nitrobacter with an energy-dependent control mechanism of CO2 assimilation.
添加还原型烟酰胺腺嘌呤二核苷酸(NADH)可使维氏硝化杆菌无细胞提取物的二氧化碳固定作用增强。然而,即使在没有NADH的情况下,1,5-二磷酸核酮糖也能增强二氧化碳固定作用。磷酸核酮糖激酶(EC 2.7.1.19)是维氏硝化杆菌提取物中被NADH特异性激活的酶。磷酸吡哆醛抑制维氏硝化杆菌的二氧化碳固定作用和NADH激活的磷酸核酮糖激酶。然而,它并不影响菠菜叶片中的磷酸核酮糖激酶。由于菠菜的这种酶也不需要还原型吡啶核苷酸,因此看来磷酸吡哆醛仅干扰NADH的结合,而不干扰5-磷酸核酮糖和5'-三磷酸腺苷的结合。NADH对磷酸核酮糖激酶活性的调节为维氏硝化杆菌提供了一种依赖能量的二氧化碳同化控制机制。