多头绒泡菌中失活的鸟氨酸脱羧酶修饰的胺特异性
Amine-specificity of the inactivating ornithine decarboxylase modification in Physarum polycephalum.
作者信息
Mitchell J L, Mitchell G K, Carter D D
出版信息
Biochem J. 1982 Sep 1;205(3):551-7. doi: 10.1042/bj2050551.
The enzyme catalysing the polyamine-stimulated modification of Physarum ornithine decarboxylase in vivo was partially purified and its activity on purified ornithine decarboxylase was examined with respect to its specificity for various amines. Spermidine, spermine and several polyamine analogues strongly promoted this reaction in vitro (apparent Km in the 0.1--0.5 mM range), whereas putrescine (apparent Km 5.33 mM) and several related diamines were not nearly as effective. In agreement with this, sensitivity studies performed in vivo also suggested that cellular spermidine, and not putrescine, is critical in modulating ornithine decarboxylase activity by this post-translational control. Unlike putrescine, or other diamines, 1,3-diaminopropane demonstrated a functional similarity to the polyamines in stimulating this reaction. This study has demonstrated a method whereby non-physiological amines capable of depressing ornithine decarboxylase activity by this natural feedback mechanism can be readily identified for further evaluation of their potential use in the experimental and medical control of polyamine biosynthesis.
对在体内催化多头绒泡菌鸟氨酸脱羧酶多胺刺激修饰的酶进行了部分纯化，并针对其对各种胺的特异性，检测了其对纯化的鸟氨酸脱羧酶的活性。亚精胺、精胺和几种多胺类似物在体外强烈促进了该反应（表观 Km 在 0.1 - 0.5 mM 范围内），而腐胺（表观 Km 为 5.33 mM）和几种相关二胺的效果则差得多。与此一致的是，体内进行的敏感性研究也表明，细胞内的亚精胺而非腐胺，在通过这种翻译后调控调节鸟氨酸脱羧酶活性方面至关重要。与腐胺或其他二胺不同，1,3 - 二氨基丙烷在刺激该反应方面表现出与多胺的功能相似性。这项研究展示了一种方法，通过该方法能够轻易识别出能够通过这种天然反馈机制抑制鸟氨酸脱羧酶活性的非生理性胺，以便进一步评估它们在多胺生物合成的实验和医学控制中的潜在用途。
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