METALLOTHIONEIN-LIKE PROTEIN IN MAMMALIAN BRAIN

我们的目标是进一步表征生物化学性质 最近从大鼠脑中分离出金属硫蛋白样蛋白， 确定其在预防重金属神经毒性中的可能作用。 这种小分子量蛋白质（Mr小于10，000）具有洗脱 体积（Ve/Vo）为2.06，其合成受到锌和铜的刺激，但 而不是镉，锌刺激蛋白质结合了大量的 [35]半胱氨酸。 据推测，这种金属硫蛋白样 蛋白质可能参与（a）锌血液稳态，（B）锌转运，（c） 在金属解毒中，或者（d）在与突触相关的事件中， 功能协调发展的 锌在神经化学和神经毒理学中的重要性 当人们意识到锌维持功能和/或 已知超过235种金属酶和/或金属蛋白的结构 参与碳水化合物、脂质、蛋白质的代谢， 核酸 此外，慢性锌丢失与 小脑功能障碍、厌食、味觉减退、嗅觉减退、夜间受损 视力、无脑畸形以及学习和行为模式的改变。 上 另一方面，在遗传性视网膜营养不良中检测到锌过量， 多发性硬化、皮克病、嗜苏丹性白质营养不良和劳氏病 综合征 大脑的金属硫蛋白样蛋白在多大程度上 这些疾病状态的改变是不值得研究的。 的 具体的目的是进一步表征的生化特性， 通过使用肝金属硫蛋白作为标准， 采用包括在SephadexG-75柱上凝胶过滤的技术， DEAE-Sephadex A-25柱，聚丙烯酰胺凝胶交换层析 非变性凝胶电泳，色谱聚焦，高效 液相色谱和氨基酸分析。 可能的区域 金属硫蛋白样蛋白在脑中的分布，其锌 浓度不均匀，将通过放射免疫测定法进行 （RIA）。 此外，这种蛋白质可能的脂解活性将 进行评估。 此外，这种合成的调节 金属硫蛋白样蛋白将通过使用培养物来研究 使用神经元作为模型，肝细胞作为标准的系统： 通过研究锌离子、糖皮质激素、肾上腺素、-金属 以及已知诱导肝金属硫蛋白合成的激素。

Our goal is to characterize further the biochemical properties of a metallothionein-like protein recently isolated from the rat brain, and to determine its possible role in preventing neurotoxicity from heavy metals. This small molecular weight protein (Mr less than 10,000), has an elution volume (Ve/Vo) of 2.06, its synthesis is stimulated by zinc and copper but not cadmium, and the zinc-stimulated protein incorporates large quantities of [35]S-cysteine. It is hypothesized that this metallothionein-like protein may be involved (a) in zinc hemeostasis, (b) in zinc transport, (c) in metal detoxification, or perhaps (d) in events related to synaptic functions. The importance of zinc in neurochemistry and neurotoxicology becomes apparent when one realizes that zinc maintains the function and/or the structure of more than 235 metalloenzymes and/or metalloproteins known to participate in the metabolism of carbohydrates, lipids, proteins, and nucleic acids. Furthermore, chronic zinc loss is associated with cerebellar dysfunction, anorexia, hypogeusia, hyposmia, impaired night vision, anencephaly, and altered learning and behavior patterns. On the other hand, zinc excess has been detected in inherited retinal dystrophy, multiple sclerosis, Pick's disease, sudanophile leucodystrophy, and Lowe's syndrome. To what extent the brain's metallothionein-like protein is altered in these disease states is not known deserving investigation. The specific aims are to characterize further the biochemical properties of this protein by using the hepatic metallothionein as a standard and by employing techniques involving gel filtration on Sephadex G-75 columns, ion exchange chromatography on DEAE-Sephadex A-25 columns, polyacrylamide gel electrophoresis on non-denaturing gel, chromatofocusing, high performance liquid chromatography, and amino acid analysis. The possible regional distribution of metallothionein-like protein in the brain, whose zinc concentration is nonuniform, will be carried out by radioimmunoassay (RIA). In addition, the possible lipolytic activity of this protein will be assessed. Furthermore, the regulation of the synthesis of this metallothionein-like protein will be investigated by employing a culture system that uses neurons as a model and the hepatocytes as a standard: and by studying the effects of Za++, glucocorticoids and epinephrine, -ametal and hormones known to induce the synthesis of the hepatic metallothionein.