Weiss R L, Davis R H
J Bacteriol. 1977 Feb;129(2):866-73. doi: 10.1128/jb.129.2.866-873.1977.
The response of Neurospora to changes in the availibility of exogenous arginine was investigated. Upon addition of arginine to the growth medium, catabolism is initiated within minutes. This occurs prior to expansion of the arginine pool or augmentation of catabolic enzyme levels. (Basal levels are approximately 25% of those found during growth in arginine-supplemented medium.) Catabolism of arginine is independent of protein synthesis, indicating that the catabolic enzymes are active but that arginine is not available for catabolism unless present in the medium. Upon exhaustion of the supply of exogenous arginine, catabolism ceases abruptly, despite an expanded arginine pool and induced levels of the catabolic enzymes. The arginine pool supports protein synthesis until the cells regain their normal capacity for endogenous arginine synthesis. These observations, combined with the known small level of induction of arginine catabolic enzymes, non-repressibility of most biosynthetic enzymes, and vesicular localization of the bulk of the arginine pool, suggest that compartmentation plays a significant role in controlling arginine metabolism in Neurospora.
对粗糙脉孢菌对外源精氨酸可用性变化的反应进行了研究。在向生长培养基中添加精氨酸后，几分钟内就会启动分解代谢。这发生在精氨酸库扩大或分解代谢酶水平增加之前。（基础水平约为在添加精氨酸的培养基中生长时发现水平的25%。）精氨酸的分解代谢与蛋白质合成无关，这表明分解代谢酶是有活性的，但除非存在于培养基中，精氨酸无法用于分解代谢。在外源精氨酸供应耗尽时，尽管精氨酸库扩大且分解代谢酶水平升高，分解代谢仍会突然停止。精氨酸库支持蛋白质合成，直到细胞恢复其正常的内源性精氨酸合成能力。这些观察结果，结合已知的精氨酸分解代谢酶的低水平诱导、大多数生物合成酶的不可抑制性以及大部分精氨酸库的囊泡定位，表明区室化在控制粗糙脉孢菌中的精氨酸代谢中起着重要作用。
