MacDonald J I, Weeks G
Department of Microbiology, University of British Columbia, Vancouver, Canada.
FEBS Lett. 1988 Sep 26;238(1):9-12. doi: 10.1016/0014-5793(88)80214-x.
Plasma membrane enriched fractions of Dictyostelium discoideum contain a Des-insensitive ATPase activity that can be fractionated by DEAE-Sephacel into a major vanadate-sensitive activity and a minor vanadate-insensitive activity. The vanadate-insensitive activity hydrolyzed pyrophosphate considerably more rapidly than ATP or any other substrate tested, and the enzyme was therefore designated a pyrophosphatase. The enzyme had no activity on AMP or p-nitrophenyl phosphate. The pyrophosphatase activity was maximal at alkaline pH values and stimulated by Mg2+ but not by Ca2+, properties of the enzyme that are very similar to those of the previously characterized pyrophosphatases of the plant tonoplast membrane. The pyrophosphatase activity of total membrane extracts changed very little during Dictyostelium differentiation.
盘基网柄菌的富含质膜的组分含有一种对去铁胺不敏感的ATP酶活性，该活性可通过DEAE-琼脂糖凝胶柱层析分离成一种主要的对钒酸盐敏感的活性和一种次要的对钒酸盐不敏感的活性。对钒酸盐不敏感的活性水解焦磷酸的速度比ATP或任何其他测试底物快得多，因此该酶被指定为焦磷酸酶。该酶对AMP或对硝基苯磷酸没有活性。焦磷酸酶活性在碱性pH值下最高，并受到Mg2+的刺激，但不受Ca2+的刺激，该酶的这些特性与先前表征的植物液泡膜焦磷酸酶的特性非常相似。在盘基网柄菌分化过程中，总膜提取物的焦磷酸酶活性变化很小。
