Flamigni F, Marmiroli S, Guarnieri C, Caldarera C M
Dipartimento di Biochimica, Università di Bologna, Italy.
Biochem Biophys Res Commun. 1990 Oct 30;172(2):939-44. doi: 10.1016/0006-291x(90)90766-g.
Addition of spermidine to Friend erythroleukemia cells caused a rapid decay of ornithine decarboxylase (ODC) activity and the accumulation of a ODC-antizyme complex. The induction of antizyme only partially accounted for the decrease of ODC activity by a direct inhibition of the enzyme. However, the antizyme induction was accompanied by a marked reduction of the half-life of ODC. Shift of the cells to an ATP-depleting medium prevented the spermidine-elicited decay of ODC activity as well as the accumulation of ODC-antizyme complex. However, ODC appeared to be stabilized even when ATP depletion was performed 40 min after spermidine addition, in the presence of high levels of antizyme. Similar results were obtained by treating the cells with phenanthroline, a heavy metal chelator and protease inhibitor. These findings indicate that ATP and some metalloprotease(s) may be involved in the degradation pathway of ODC, even in the presence of high levels of polyamines.
向弗氏红白血病细胞中添加亚精胺会导致鸟氨酸脱羧酶（ODC）活性迅速衰减，并积累ODC-抗酶复合物。抗酶的诱导仅部分解释了由于直接抑制该酶而导致的ODC活性降低。然而，抗酶诱导伴随着ODC半衰期的显著缩短。将细胞转移至消耗ATP的培养基中可阻止亚精胺引发的ODC活性衰减以及ODC-抗酶复合物的积累。然而，即使在添加亚精胺40分钟后进行ATP消耗，在抗酶水平较高的情况下，ODC似乎仍能保持稳定。用菲咯啉（一种重金属螯合剂和蛋白酶抑制剂）处理细胞也获得了类似的结果。这些发现表明，即使在多胺水平较高的情况下，ATP和某些金属蛋白酶可能也参与了ODC的降解途径。
