ATP-dependent regulation of rabbit myocardial cytosolic calcium-independent phospholipase A2.
ATP-dependent regulation of rabbit myocardial cytosolic calcium-independent phospholipase A2.
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DOI：
10.1016/s0021-9258(18)98718-1
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发表时间：
1991-08
期刊：
影响因子：
--
通讯作者：
S. L. Hazen;Richard W. Gross
中科院分区：
文献类型：
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作者：
S. L. Hazen;Richard W. Gross
我们在这里报告，兔心肌胞浆钙非依赖性磷脂酶A2存在作为一个高分子量的催化和调节多肽，其活性和稳定性的影响，通过与ATP的特定相互作用组成的复合物。多种证据证明了催化复合物与ATP之间相互作用的功能意义，包括：1）腺嘌呤核苷酸三磷酸减弱天然胞质磷脂酶A2的热变性速率; 2）ATP以不依赖于聚集底物的浓度、界面性质和物理状态的方式增加磷脂水解的初始速率; 3）腺嘌呤核苷酸三磷酸减弱了必需巯基残基对5，5 '-二硫代双（2-硝基苯甲酸）;和4）催化复合物特异性地和可逆地结合ATP亲和基质，尽管纯化的40-kDa催化亚基既不与ATP亲和基质结合，也不受ATP依赖性活化和稳定化的影响。催化和调节元件的功能上解决了差热灭活和ATP调节磷脂酶A2催化复合物重组高度纯化的催化和部分纯化的调节蛋白。因此，ATP浓度的改变影响心肌细胞质钙非依赖性磷脂酶A2催化复合物的活性和寿命，从而潜在地调节细胞内第二信使的释放，并促进膜物理性质的适应性改变。
We report here that rabbit myocardial cytosolic calcium-independent phospholipase A2 exists as a high molecular weight complex comprised of catalytic and regulatory polypeptides whose activity and stability are influenced by specific interactions with ATP. Multiple lines of evidence document the functional significance of interactions between the catalytic complex and ATP including: 1) adenine nucleotide triphosphates attenuate the rate of thermal denaturation of native cytosolic phospholipase A2; 2) ATP augments the initial rate of phospholipid hydrolysis in a manner independent of the concentration, interfacial properties, and physical state of aggregated substrate; 3) adenine nucleotide triphosphates attenuate the reactivity of an essential thiol residue to covalent modification by 5,5'-dithiobis(2-nitrobenzoic acid); and 4) the catalytic complex specifically and reversibly binds to ATP affinity matrices, although the purified 40-kDa catalytic subunit neither binds to ATP affinity matrices nor is subject to ATP-dependent activation and stabilization. The catalytic and regulatory elements were functionally resolved by differential thermal inactivation and the ATP-regulatable phospholipase A2 catalytic complex was reassembled by reconstitution of highly purified catalytic and partially purified regulatory proteins. Thus, alterations in ATP concentration influence the activity and longevity of the myocardial cytosolic calcium-independent phospholipase A2 catalytic complex, thereby potentially modulating the release of lipidic second messengers and facilitating adaptive alterations in membrane physical properties.