内分泌
词汇介绍
拓展阅读
解析
catecholamine 英 /ˌkætəˈkɒləˌmiːn/ 美 /ˌkætəˈtʃoʊləˌmɪn; ˌkætəˈkoʊləˌmin/
释 义 n. 儿茶酚胺
例 句 Primary culture of human embryonic hepatocytes was employed to study the effects of catecholamine and thrombin on the secretion of histidine rich glycoprotein(HRG). 采用人胎肝细胞原代培养方法，观察儿茶酚胺和凝血酶对肝细胞富组氨酸糖蛋白（HRG）分泌的影响。
概述
概述
儿茶酚胺（简称CA）是一种单胺神经递质，一个有机化合物，其具有儿茶酚（苯具有两个羟基的侧基彼此相邻）和副作用链胺。邻苯二酚可以是一个自由分子，也可以是较大分子的取代基，在这里它代表1,2-二羟基苯甲基。儿茶酚胺来源于氨基酸 酪氨酸，酪氨酸来源于饮食以及苯丙氨酸的合成。儿茶酚胺是水溶性的，在循环中与血浆蛋白结合50%。儿茶酚胺中包括肾上腺素，去甲肾上腺素和多巴胺。酪氨酸选自苯丙氨酸通过创建羟化通过酶苯丙氨酸羟化酶，酪氨酸也直接从饮食蛋白中摄取。
生物合成
多巴胺是由DOPA合成的第一种儿茶酚胺。反过来，去甲肾上腺素和肾上腺素衍生自多巴胺的进一步代谢修饰。多巴胺羟化酶需要铜作为辅因子，而DOPA脱羧酶需要PLP，通过主要代谢途径进行儿茶酚胺生物合成的速率限制步骤是L-酪氨酸羟基化为L-DOPA。儿茶酚胺的合成受到α-甲基-对-酪氨酸（AMPT）的抑制，后者可抑制酪氨酸羟化酶。氨基酸苯丙氨酸和酪氨酸是儿茶酚胺的前体。在血浆和大脑中都发现了这两种氨基酸。在哺乳动物中，酪氨酸可由饮食中的苯丙氨酸通过苯丙氨酸羟化酶（在肝脏中大量发现）形成。苯丙氨酸羟化酶的量不足会导致苯丙酮尿症，这是一种代谢性疾病，除非通过饮食操作进行治疗，否则会导致智力缺陷。儿茶酚胺合成通常被认为是开始于酪氨酸，酶酪氨酸羟化酶（TH）转换的氨基酸大号-酪氨酸转化为3,4-二羟基苯丙氨酸（L-DOPA）。TH 对L-酪氨酸的羟基化作用导致DA前体L-DOPA的形成，该前体被芳族L-氨基酸脱羧酶（AADC）代谢为递质多巴胺。这个步骤发生得如此之快，以至于在不先抑制AADC的情况下很难测量大脑中的L-DOPA。在使用DA作为递质的神经元中，L的脱羧-多巴胺的DOPA是形成递质的最后步骤；然而，在那些使用去甲肾上腺素或肾上腺素作为递质的神经元中，也存在将多巴胺转化为去甲肾上腺素的多巴胺β-羟化酶（DBH）。在肾上腺素是递质的其他神经元中，第三种酶苯乙醇胺N-甲基转移酶（PNMT）将去甲肾上腺素转化为肾上腺素。因此，使用肾上腺素作为递质的细胞包含四种酶（TH，AADC，DBH和PNMT），而去甲肾上腺素神经元仅包含三种酶（缺少PNMT），而多巴胺细胞仅包含两种酶（TH和AADC）。
降解
儿茶酚胺在血液中循环时的半衰期为几分钟，它们可以通过儿茶酚-O-甲基转移酶（COMT）甲基化或通过单胺氧化酶（MAO）脱氨来降解。MAOI与MAO结合，从而防止其分解儿茶酚胺和其他单胺。儿茶酚胺的分解代谢是由两种主要的酶介导的：存在于细胞突触间隙和细胞质中的儿茶酚-O-甲基转移酶（COMT）和位于线粒体膜中的单胺氧化酶（MAO）。两种酶都需要辅因子：COMT使用Mg 2+作为辅因子，而MAO使用FAD。分解代谢过程的第一步由MAO或COMT介导，这取决于儿茶酚胺的组织和位置（例如，裂隙中儿茶酚胺的降解由COMT介导，因为MAO是线粒体酶）。该途径的下一个分解代谢步骤涉及乙醇脱氢酶，醛脱氢酶和醛还原酶。肾上腺素和去甲肾上腺素的最终产物是香草醛酸（VMA），可从尿中排出。多巴胺分解代谢导致高香草酸（HVA）的产生。
复制标题新蛋白激酶C参与凡纳滨对虾血细胞儿茶酚胺生物合成和免疫活性调节
发表时间：2019-09-26
影响指数：3.1
作者： Chin-Chyuan Chang
期刊：Dev Com Immunol
Through specific signal transduction pathways, multiple cellular processes including differentiation, cell growth, secretion and muscle contraction were regulated by varied isotypes of protein kinase C (PKC) following the difference of their tissue distributions and localization within the cells. Cells response to signals through phosphorylation of critical targeted proteins following triggering the turnover of inositol phospholipids (IPs), which generates diacylglycerol (DG) and mobilizes Ca2+, are activated to result in the cell activation. Upon elucidating the primary structure and biochemical properties, and the difference of demand on DGs, phorbol esters, acidic phospholipids such as phosphatidylserine (PS), and the presence of Ca2+, there were three classes including classical or conventional (c)PKC, novel (n)PKC, and atypical (a)PKC isotypes reviewed by Ohno and Nishizuka. Base on the well preserved catalytic and regulatory domains peptidic sequences of the different vertebrate PKC families, the use of antibodies could be the strategy for detecting specific protein with antibodies obtained against mammalian molecules in invertebrates. In mollusks, different isotypes of cPKC (DG- and Ca2+-dependent) and nPKC (DGdependent and Ca2+-independent) were detected in the cytosolic fraction in the adductor and retractor muscles of Mytilus galloprovincialis by immunoblot analysis. In crustaceans, PKCα (a cPKC isotype) in regulating vitellogenin uptake in the ovary of Cherax quadricarinatus was identified by rabbit polyclonal anti-PKC isoenzyme antibodies. In Penaeus monodon, using mammalian PKC antibodies, PKCδ (an nPKC isotype) was purified from the hepatopancreas. In addition, the preserved domains sequences of aPKC in Macrobrachium rosenbergii and nPKC in Litopenaeus vannamei were isolated using designed degenerate primers and the rapid amplification of cDNA ends. Using staurosporine (a PKC inhibitor) and phorbol 12- myristate 13-acetate (PMA, a PKC activator), Johansson and Söderhäll reported that the degranulation of crayfish granular blood cells and the release of the proPO activating system can be mediated by two endogenous ligands, a 76-kDa cell adhesion protein (peroxinectin) or a β-l,3-glucan binding protein through PKC signaling transduction. Moreover, Ng et al. indicated that extracellular traps for phagocytosis were revealed in L. vannamei responding to PMA stimulation. These revealed that not only the structural domains of PKC isotypes but also the pharmaceuticals for PKC might be similar in either vertebrates or invertebrates.
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