Murakami Y, Fujita K, Kameji T, Hayashi S
Biochem J. 1985 Feb 1;225(3):689-97. doi: 10.1042/bj2250689.
A new method was developed for the assay of ornithine decarboxylase (ODC)-antizyme complex, in which alpha-difluoromethylornithine (DFMO)-inactivated ODC was used to release active ODC competitively from the complex. ODC-antizyme complex was present in the extracts of hepatoma tissue-culture (HTC) cells and of ODC-stabilized variant HMOA cells, in much larger amounts in the latter. Cellular amounts of the complex fluctuated after a change of medium in a similar manner in HTC and HMOA cells, increasing during the period of ODC decay. After treatment with cycloheximide, the decay of ODC-antizyme complex in HMOA cells was more rapid than the decay of free ODC, but it was much slower than the decay of free ODC or complexed ODC in HTC cells. Administration of putrescine caused a rapid increase in the amount of ODC-antizyme complex in both HTC and HMOA cells, but nevertheless the decay of total ODC (free ODC plus ODC-antizyme complex) was more rapid with putrescine than with cycloheximide. These results suggested the possibility that ODC is degraded through complex-formation with antizyme. In contrast with complexed antizyme, free antizyme was not stabilized in HMOA cells.
开发了一种新的方法来测定鸟氨酸脱羧酶（ODC）-抗酶复合物，其中使用α-二氟甲基鸟氨酸（DFMO）灭活的ODC从复合物中竞争性地释放活性ODC。ODC-抗酶复合物存在于肝癌组织培养（HTC）细胞和ODC稳定变体HMOA细胞的提取物中，后者中的含量要大得多。在HTC和HMOA细胞中，培养基更换后复合物的细胞含量以类似方式波动，在ODC衰减期间增加。用环己酰亚胺处理后，HMOA细胞中ODC-抗酶复合物的衰减比游离ODC的衰减更快，但比HTC细胞中游离ODC或复合ODC的衰减慢得多。给予腐胺会导致HTC和HMOA细胞中ODC-抗酶复合物的量迅速增加，但腐胺处理后总ODC（游离ODC加ODC-抗酶复合物）的衰减比环己酰亚胺处理后更快。这些结果提示了ODC通过与抗酶形成复合物而降解的可能性。与复合抗酶不同，游离抗酶在HMOA细胞中不稳定。
