Polyphosphate kinase of Acinetobacter sp. strain ADP1: purification and characterization of the enzyme and its role during changes in extracellular phosphate levels.
Polyphosphate kinase of Acinetobacter sp. strain ADP1: purification and characterization of the enzyme and its role during changes in extracellular phosphate levels.
复制标题
不动杆菌属的多磷酸激酶。
DOI：
10.1128/aem.65.9.3780-3786.1999
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发表时间：
1999
影响因子：
4.4
通讯作者：
Keasling,JD
中科院分区：
文献类型：
--
作者：
Trelstad,PL;Purdhani,P;Geissdörfer,W;Hillen,W;Keasling,JD
聚磷酸盐（polyP）是一种普遍存在的生物聚合物，其功能和代谢尚不完全清楚。研究了不动杆菌多磷酸激酶（PPK）的活性。将积累大量聚P的生物体菌株ADP 1纯化至均一并表征。这种酶是一种79 kDa的单体，它将ATP的末端磷酸盐添加到聚P的生长链上。PPK对镁浓度敏感，在3 mM MgCl2存在下发生最佳活性。最适pH值为pH 7和8之间，并在较低的pH值下发生的活动显着减少。最大活性发生在40 ° C。PPK的半饱和ATP浓度为1 mM，最大PPK活性为28 nmol聚P单体/μ g蛋白/min。PPK是主要的，但不是唯一的，酶负责生产聚P在不动杆菌属。菌株ADP 1。在低磷（Pi）条件下，尽管ppk基因的强烈诱导，但聚P净合成活性下降，并且不动杆菌中的聚P水平接近于零。菌株ADP 1。一旦将过量的磷酸盐添加到PI饥饿的培养物中，聚P合成活性和聚P水平均急剧上升。聚磷酸酶降解活性的增加，这似乎主要是由于一个聚磷酸酶，而不是PPK反向工作，在低-Piconditions下生长的培养物中检测到。当加入磷酸盐时，这种活性下降。
Polyphosphate (polyP) is a ubiquitous biopolymer whose function and metabolism are incompletely understood. The polyphosphate kinase (PPK) ofAcinetobactersp. strain ADP1, an organism that accumulates large amounts of polyP, was purified to homogeneity and characterized. This enzyme, which adds the terminal phosphate from ATP to a growing chain of polyP, is a 79-kDa monomer. PPK is sensitive to magnesium concentrations, and optimum activity occurs in the presence of 3 mM MgCl2. The optimum pH was between pH 7 and 8, and significant reductions in activity occurred at lower pH values. The greatest activity occurred at 40°C. The half-saturation ATP concentration for PPK was 1 mM, and the maximum PPK activity was 28 nmol of polyP monomers per μg of protein per min. PPK was the primary, although not the sole, enzyme responsible for the production of polyP inAcinetobactersp. strain ADP1. Under low-phosphate (Pi) conditions, despite strong induction of theppkgene, there was a decline in net polyP synthesis activity and there were near-zero levels of polyP inAcinetobactersp. strain ADP1. Once excess phosphate was added to the Pi-starved culture, both the polyP synthesis activity and the levels of polyP rose sharply. Increases in polyP-degrading activity, which appeared to be mainly due to a polyphosphatase and not to PPK working in reverse, were detected in cultures grown under low-Piconditions. This activity declined when phosphate was added.