BIOTINIDASE AND ITS ROLE IN BIOTIN METABOLISM

描述：生物素酶是一种负责循环利用 来自生物细胞素(epsilon-生物素-L-赖氨酸)的维生素生物素 依赖生物素的蛋白质降解形成的生物素基肽 羧基酶。生物素酶缺乏症是急性胰腺炎的主要酶缺陷 遗传型生物素反应性、晚发型多重羧基酶 缺乏症。申请人已经证明，除了它的乳沟 生物素酶将生物素转移到各种亲核受体， 包括特定的血清蛋白，在中性条件下与生物细胞素孵育 碱性酸碱度。到目前为止，他的研究小组已经在这个细胞中发现了组蛋白 血清中一组生物素标记的蛋白质。在这项拟议的研究中， 其他生物素化蛋白质和小分子将在 血清、细胞和组织中。还将确定生物素酶是否 生物素化和/或从生物素依赖的羧基酶中去除生物素 它在将生物素输送到细胞中发挥作用。为了更好地理解 这些功能和生物素酶的新陈代谢，申请人计划 正常血清和正常血清中该酶的生物化学和细胞生物学研究 组织，在各种肿瘤细胞中，以及处于生物素酶缺陷状态。这个 生物素酶在正常和临床相关组织中的亚细胞定位 培养的细胞和组织将用免疫细胞化学方法确定 技巧。摄取、周转和分泌的特点 这些细胞的生物素酶也将被测定。类似的研究将 也可以使用成纤维细胞和淋巴母细胞来完成 生物素酶缺乏症。结果将与正常的结果进行比较 并将与细胞的生化特征相关联。 生物素酶缺陷者血清生物素酶及其与其关系的研究 分子缺陷。这些结果将对预后有影响。 以及生物素酶缺陷儿童的治疗。此外，建议的 研究将提供更好的理解生物素酶在 生物素新陈代谢，将成为了解生物素代谢的范例 其他维生素。

DESCRIPTION: Biotinidase is the enzyme responsible for the recycling of the vitamin biotin from biocytin (epsilon-biotinyl-L-lysine) and biotinyl-peptides formed by the proteolytic degradation of biotin-dependent carboxylases. Biotinidase deficiency is the primary enzymatic defect in an inherited form of biotin-responsive, late-onset multiple carboxylase deficiency. The applicant has shown that in addition to its cleavage activity, biotinidase transfers biotin to various nucleophilic acceptors, including specific serum proteins, when incubated with biocytin at neutral to alkaline pH. His research group thus far has identified histones in this group of biotinylated protein in serum. In the proposed research, additional biotinylated proteins and small molecules will be identified in serum and in cells and tissues. It will also be determined if biotinidase biotinylates and/or removes biotin from biotin-dependent carboxylases and if it plays a role in transporting biotin into cells. To better understand these functions and the metabolism of biotinidase, the applicant plans to study the biochemistry and cell biology of the enzyme in normal serum and tissues, in various tumor cells, and in biotinidase-deficient states. The subcellular localization of biotinidase in normal and clinically relevant cultured cells and tissues will be determined using immunocytochemical techniques. The characteristics of uptake, turnover, and secretion of biotinidase by these cells will also be determined. Similar studies will also be performed using fibroblasts and lymphoblasts of individuals with biotinidase deficiency. The results will be compared to those of normal cells and will be correlated with the biochemical characteristics of biotinidase in sera of biotinidase-deficient individuals and with their molecular defects. These results will have implications for the prognosis and treatment of biotinidase-deficient children. In addition, the proposed research will provide a better understanding of the role of biotinidase in biotin metabolism and will be a paradigm for understanding the metabolism of other vitamins.