Calcium-dependent regulation of brain adenylate cyclase.
Calcium-dependent regulation of brain adenylate cyclase.
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脑腺苷酸环化酶的钙依赖性调节。
DOI：
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发表时间：
1978
期刊：
影响因子：
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通讯作者：
D. J. Wolff
中科院分区：
文献类型：
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作者：
M. Brostrom;C. Brostrom;B. Breckenridge;D. J. Wolff
大鼠大脑皮质颗粒制剂的腺苷酸环化酶活性由两个贡献成分组成，其中只有一个需要CDR才能活性。cdr依赖成分被高比例的Mg2+和Ca2+抑制，以双相方式（激活和抑制）响应游离Ca2+浓度的增加，被0.1至0.4 mM氯丙嗪抑制，并被1至100微米的可卡因激活。这种酶约占皮层匀浆的80%的基本活性，在45℃的匀浆预处理过程中是稳定的，但在制备颗粒部分过程中，CDR的去除使其完全失活。不依赖于CDR的腺苷酸环化酶活性在制备颗粒组分时不受CDR去除的影响，在Mg2+与Ca2+的高比例下活性升高，被Ca2+抑制，0.1至0.4 mM氯丙嗪不受影响，1至100微米可卡因轻微抑制，并且在45度均浆预处理期间不稳定。腺苷酸环化酶活性的CDR依赖组分被5mm NaF不同程度地激活，这取决于检测中存在的CDR浓度。NaF降低了在最佳CDR浓度下产生一半最大速度所需的CDR浓度。NaF的激活需要Ca2+的存在，EGTA立即完全逆转。相比之下，对CDR没有反应的成分被NaF激活了4到5倍。这种激活不受Ca2+或CDR的影响，也不被EGTA逆转。本文讨论了二价阳离子对CDR依赖酶的影响，以及CDR的阳离子结合特性。cdr依赖形式的腺苷酸环化酶与该酶的其他形式的关系仍有待确定。
The adenylate cyclase activity of a particulate preparation of rat cerebral cortex is comprised of two contributing components, only one of which requires a CDR for activity. The CDR-dependent component was inhibited by high ratios of Mg2+ to Ca2+, responded in a biphasic manner (activation then inhibition) to increasing free Ca2+ concentrations, was inhibited by 0.1 to 0.4 mM chlorpromazine, and was activated by 1 to 100 micrometer cocaine. This enzyme form, which represented approximately 80% of tge basal activity of a cortex homogenate, was stable during pretreatment of homogenates at 45 degrees C but was completely deactivated by the removal of CDR during the preparation of the particulate fraction. Adenylate cyclase activity that did not depend on CDR was unaffected by the removal of CDR during the preparation of the particulate fraction, had elevated activity at high ratios of Mg2+ to Ca2+, was inhibited by Ca2+, was unaffected by 0.1 to 0.4 mM chlorpromazine and was slightly inhibited by 1 to 100 micrometer cocaine, and was not stable during pretreatment of homogenates at 45 degrees. The CDR-dependent component of adenylate cyclase activity was activated by 5 mM NaF to varying degrees depending on the concentration of CDR present in the assay. NaF decreased the concentration of CDR required to produce half-maximal velocity obtained at optimal concentrations of CDR. Activation by NaF required the presence of Ca2+ and was immediately and completely reversed by EGTA. In contrast, the component that did not respond to CDR was activated four- to fivefold by NaF. This activation was not influenced by Ca2+ or CDR and was not reversed by EGTA. The observed effects of effects of divalent cations on the CDR-dependent enzyme are discussed in relation to the cation-binding properties of CDR. The relationship of the CDR-dependent form of adenylate cyclase to other forms of this enzyme remains to be determined.