Hilt W, Heinemeyer W, Wolf D H
Institut für Biochemie, Universität Stuttgart, Deutschland.
Enzyme Protein. 1993;47(4-6):189-201. doi: 10.1159/000468678.
Proteasomes are large multicatalytic protease complexes found in the cytoplasm and nucleus of all eukaryotic cells. 20S proteasomes are cylindrically shaped particles composed of a set of different subunits arranged in a stack of 4 rings with 7-fold symmetry. In yeast 14 different genes are known, which are proposed to code for the complete set of 20S proteasomal subunits. They can be divided in 7 alpha- and 7 beta-type subunits. 26S proteasomes are even larger proteinase complexes which contain the 20S proteasome as the functional proteolytic core. They degrade ubiquitinylated proteins in vitro. Several yeast 26S proteasome subunits have been characterized as members of a novel ATPase family. Studies with yeast 20S and 26S proteasome mutants uncovered the function of proteasomes in stress-dependent and ubiquitin-mediated proteolytic pathways. Proteasomes are important for cellular regulation, cell differentiation, adaptation to environmental changes and are involved in cell cycle control.
蛋白酶体是存在于所有真核细胞的细胞质和细胞核中的大型多催化蛋白酶复合物。20S蛋白酶体是圆柱形颗粒，由一组不同的亚基组成，这些亚基排列成具有七重对称性的4个环的堆叠。在酵母中，已知有14个不同的基因，它们被认为编码20S蛋白酶体亚基的完整集合。它们可分为7种α型和7种β型亚基。26S蛋白酶体是更大的蛋白酶复合物，它包含20S蛋白酶体作为功能性蛋白水解核心。它们在体外降解泛素化蛋白。几种酵母26S蛋白酶体亚基已被鉴定为一个新型ATP酶家族的成员。对酵母20S和26S蛋白酶体突变体的研究揭示了蛋白酶体在应激依赖性和泛素介导的蛋白水解途径中的功能。蛋白酶体对细胞调节、细胞分化、适应环境变化很重要，并参与细胞周期控制。
