POLYAMINE BIOSYNTHESIS AND FUNCTION

多胺、腐胺、亚精胺和 精胺是所有活细胞中主要的多元化合物。这些 胺已经显示出对于许多相关的体系是重要的， 生长和分化。我们一直对这些 多胺是如何合成的，它们的生物合成和降解 调节，它们的生理功能，以及它们如何在体内起作用。 为此目的，我们在每一个 在大肠杆菌和酵母菌中的生物合成步骤 啤酒..我们目前的研究旨在扩大我们的 这些胺的生物化学、调节和遗传学研究 和S.啤酒。于本 一年来，我们特别感兴趣的是研究 鸟氨酸脱羧酶是一个关键酶 多胺的形成，特别是在研究 多胺的生理功能。鸟氨酸 脱羧酶水平被亚精胺的加入抑制 我们发现，与以前的报道相反， 在文献中，该调节的一个重要部分涉及 诱导蛋白水解活性。有趣的是，这个归纳法 如果蛋白质合成受到抑制，则不发生，表明参与了 一种新的，还未鉴定的蛋白质其他研究 涉及：（1）多胺缺乏对核糖体 作为我们正在进行的多胺作用研究的一部分 在蛋白质生物合成中，以及（2）与Arthur合作 Kornberg多胺水平和 E. coli和革兰氏阳性菌S.酿酒，使用我们的 需要多胺的突变体和Kornberg突变体 酵母中的多磷酸途径。

The polyamines, putrescine, spermidine, and spermine, are major polybasic compounds in all living cells. These amines have been shown to be important for many systems related to growth and differentiation. We have been interested in how these polyamines are synthesized, how their biosynthesis and degradation are regulated, their physiologic functions, and how they act in vivo. For this purpose we have constructed null mutants in each of the biosynthetic steps in both Escherichia coli and in Saccharomyces cerevisiae.. Our present studies are directed at extending our studies on the biochemistry, regulation and genetics of these amines and of the biosynthetic enzymes in S. cerevisiae. During the current year we have been particularly interested in studying the regulation of the enzyme ornithine decarboxylase which is a key enzyme in the formation of the polyamines, and is of special interest in studies on the physiological function of the polyamines. The ornithine decarboxylase levels are repressed by the addition of spermidine to the medium, and we have found that, contrary to previous reports in the literature, an important part of this regulation involves the induction of a proteolytic activity. Interestingly this induction does not occur if protein synthesis is inhibited, indicating the involvement of a new, and, as yet unidentified, protein. Other studies have involved: (1) the effect of polyamine deficiency on the ribosomal pattern as part of our ongoing studies on the role of the polyamines in protein biosynthesis, and (2) in collaboration with Arthur Kornberg a quantitative comparison of polyamine levels and polyphosphate levels in E. coli and S. cerevisiae, using our polyamine-requiring mutants and Kornberg's mutants in the polyphosphate pathways in yeast.