Abstract—Proteasomes are key components of the ubiquitin–proteasome system. Various forms of proteasomes are known. During aging, disturbances in the functioning of proteasomes have been revealed, as well as increased expression of their particular forms. Considering these data, we studied the expression of genes encoding the constitutive and immune subunits of proteasomes in cerebral cortex samples from C57BL/6 mice at the ages of 60, 190, 380, and 720 days. In addition, the contents of constitutive and immune proteasome subunits, chymotrypsin-like and caspase-like activities of proteasome pools, as well as the activity of the β5i immune subunit were studied in tissue homogenates. The chymotrypsin-like activity and the activity of the β5i subunit of different forms of proteasomes separated by electrophoresis in native gel were characterized. Compared with samples from young animals, in the cerebral cortex of animals at an age of 720 days the following changes in the expression patterns of proteasome genes were revealed: a decreased expression of the PSMB5 gene encoding constitutive proteasome subunit β5; increased expression of genes encoding immune proteasome subunits β5i and β1i. In tissue homogenates of aged mice, an increase in the content of immune subunits β1i and β2i was shown. In samples from old animals, chymotrypsin-like activity was decreased and a tendency to a decrease in caspase-like activity of proteasomes as well as the β5i subunit activity was revealed. Analysis of the activity of native complexes in tissues obtained from old animals revealed decreased chymotrypsin-like activity of 26S and 20S proteasomes containing the β5i subunit. Based on the obtained data, it can be assumed that changes in the pool of nonconstitutive proteasomes reflect aging-associated adaptive processes in the mouse brain.

摘要—蛋白酶体是泛素-蛋白酶体系统的关键组成部分。已知多种形式的蛋白酶体。在衰老过程中，蛋白酶体的功能受到干扰，并且其特定形式的表达增加。考虑到这些数据，我们研究了 60、190、380 和 720 天 C57BL/6 小鼠大脑皮层样本中编码蛋白酶体组成亚基和免疫亚基的基因的表达。此外，还研究了组织匀浆中组成型和免疫型蛋白酶体亚基的含量、蛋白酶体池的胰凝乳蛋白酶样和半胱天冬酶样活性以及β5i免疫亚基的活性。对通过非变性凝胶电泳分离的不同形式的蛋白酶体的胰凝乳蛋白酶样活性和β5i亚基的活性进行了表征。PSMB5基因编码组成型蛋白酶体亚基β5；编码免疫蛋白酶体亚基 β5i 和 β1i 的基因表达增加。在老年小鼠的组织匀浆中，免疫亚基β1i和β2i的含量有所增加。在年老动物的样本中，胰凝乳蛋白酶样活性降低，并且蛋白酶体的半胱天冬酶样活性以及β5i亚基活性有降低的趋势。对年老动物组织中天然复合物活性的分析表明，含有 β5i 亚基的 26S 和 20S 蛋白酶体的胰凝乳蛋白酶样活性降低。根据获得的数据，可以假设非组成型蛋白酶体库的变化反映了小鼠大脑中与衰老相关的适应性过程。