Cleary M L, Garvin R T, James E
Mol Gen Genet. 1977 Nov 29;157(2):155-65. doi: 10.1007/BF00267393.
The in vitro synthesis of enzymatically-active ornithine transcarbamylase (OTCase) directed by each of the E. coli K-12 OTCase genes (argF and argI) is described. The E. coli OTCase isoenzyme subunits are not identical, whether synthesized in vivo or in vitro, the argF-coded product being about 5% smaller. The OTCase protomers are enzymatically inactive but associate in vitro to an enzymatically active multimer. The rates of subunit association of argF and argI isoenzymes are considerably different. Utilizing the facile assay protocol presented, the regulation of in vitro OTCase synthesis by the specific holorepressor of the arginine regulon is demonstrated. Calculations based upon data presented indicate that there are about 65 molecules of argR gene product per bacterium, a substantially lower estimate than previously reported.
本文描述了由大肠杆菌K-12的每个鸟氨酸转氨甲酰酶（OTCase）基因（argF和argI）指导的具有酶活性的鸟氨酸转氨甲酰酶的体外合成。大肠杆菌OTCase同工酶亚基无论在体内还是体外合成都不相同，argF编码的产物大约小5%。OTCase原体没有酶活性，但在体外会缔合成具有酶活性的多聚体。argF和argI同工酶的亚基缔合速率有很大差异。利用所提供的简便检测方案，证明了精氨酸调节子的特异性全阻遏物对体外OTCase合成的调节作用。根据所提供的数据进行的计算表明，每个细菌中约有65个argR基因产物分子，这一估计值比先前报道的要低得多。
