Li X, Coffino P
Department of Microbiology and Immunology, University of California, San Francisco 94143.
Mol Cell Biol. 1994 Jan;14(1):87-92. doi: 10.1128/mcb.14.1.87-92.1994.
Selective degradation by proteasomes of ornithine decarboxylase, the initial enzyme in polyamine biosynthesis, is mediated by the polyamine-inducible protein antizyme. Antizyme binds to a region near the N terminus of ornithine decarboxylase (X. Li and P. Coffino, Mol. Cell. Biol. 12:3556-3562, 1992). This interaction induces a conformational change in ornithine decarboxylase that exposes its C terminus and inactivates the enzyme (X. Li and P. Coffino, Mol. Cell. Biol. 13:1487-1492, 1993). Here we show that the C-terminal half of antizyme alone can inactivate ornithine decarboxylase and alter its conformation, but it cannot direct degradation of the enzyme, either in vitro or in vivo. A portion of the N-terminal half of antizyme must be present to promote degradation.
多胺生物合成途径中的起始酶——鸟氨酸脱羧酶，其通过蛋白酶体进行的选择性降解由多胺诱导蛋白抗酶介导。抗酶与鸟氨酸脱羧酶N端附近的区域结合（X. Li和P. Coffino，《分子细胞生物学》12:3556 - 3562，1992年）。这种相互作用会诱导鸟氨酸脱羧酶发生构象变化，从而暴露其C端并使该酶失活（X. Li和P. Coffino，《分子细胞生物学》13:1487 - 1492，1993年）。在此我们表明，单独的抗酶C端一半能够使鸟氨酸脱羧酶失活并改变其构象，但无论是在体外还是体内，它都不能引导该酶的降解。抗酶N端一半的一部分必须存在才能促进降解。
