Kuhn J, Somerville R L
Proc Natl Acad Sci U S A. 1971 Oct;68(10):2484-7. doi: 10.1073/pnas.68.10.2484.
A series of mutations has been isolated that confer upon amino-acid auxotrophs of Escherichia coli K-12 the ability to grow when fed various D-amino acids. Several distinct systems, mediating cellular use of the D-isomers of leucine, histidine, phenylalanine, tyrosine, tryptophan, isoleucine, and valine, can be mutationally activated. Mutations leading to D-tryptophan use (dadR) all map near purB. They result in high activities of an enzyme that deaminates D-amino acids. Neither the enzymes of the tryptophan biosynthetic pathway nor tryptophanase (EC 4.2.1.e) are involved in D-tryptophan utilization.
已分离出一系列突变，这些突变赋予大肠杆菌K - 12的氨基酸营养缺陷型在喂食各种D - 氨基酸时生长的能力。介导细胞利用亮氨酸、组氨酸、苯丙氨酸、酪氨酸、色氨酸、异亮氨酸和缬氨酸的D - 异构体的几个不同系统可通过突变激活。导致利用D - 色氨酸的突变（dadR）都定位在purB附近。它们导致一种使D - 氨基酸脱氨的酶具有高活性。色氨酸生物合成途径的酶和色氨酸酶（EC 4.2.1.e）都不参与D - 色氨酸的利用。
