Science. 1964 Aug 14;145(3633):674-9. doi: 10.1126/science.145.3633.674.
The study of metabolic regulation in microorganisms has revealed several simple but efficient regulatory circuits. In one, the operation of an entire sequence of enzymes is controlled by the activity of the initial enzyme which contains a specific inhibitor site. When this site is combined with the endproduct of the sequence, the catalytic site is rendered inactive. In another, the formation of an entire sequence of enzymes is controlled by means of a cytoplasmic mediator which blocks the transcription of the genetic message (repression) when activated by the endproduct, or which allows the transcription (induction) when activated by the substrate of the first enzyme in the sequence. Additional circuits have been proposed for the regulation of RNA and DNA synthesis. The same regulatory devices could account, in part, for intracellular metabolic control in more complex animal and plant forms. However, superimposed upon these simple control circuits will be found others which take advantage of the greater degree of organization in these cells and of the possibilities for regulating gene function that are provided by the chromosomes. The pattern of proteins with special control sites, such as have evolved in the relatively simple controls found in bacteria, may also be found essential for intercellular controls involving nervous and humoral mechanisms.
微生物代谢调节的研究揭示了几个简单但有效的调节回路。其中一个是，整个酶序列的操作受初始酶的活性控制，该酶包含一个特定的抑制剂结合位点。当该位点与序列的终产物结合时，催化位点就会失活。另一个是，整个酶序列的形成是通过细胞质介质来控制的，当被终产物激活时，细胞质介质会阻止遗传信息的转录（抑制），或者当被序列中第一个酶的底物激活时，允许转录（诱导）。还提出了其他用于调节 RNA 和 DNA 合成的电路。这些相同的调节装置部分可以解释更复杂的动物和植物形式的细胞内代谢控制。然而，在这些简单的控制电路之上，还会发现其他利用这些细胞更高程度的组织和染色体提供的调节基因功能的可能性的控制电路。具有特殊控制位点的蛋白质模式，如在细菌中发现的相对简单的控制中进化而来的蛋白质模式，对于涉及神经和体液机制的细胞间控制也可能是必不可少的。
