Wargel R J, Shadur C A, Neuhaus F C
J Bacteriol. 1970 Sep;103(3):778-88. doi: 10.1128/jb.103.3.778-788.1970.
The accumulation of d-alanine, l-alanine, glycine, and d-cycloserine in Escherichia coli was found to be mediated by at least two transport systems. The systems for d-alanine and glycine are related, and are separate from that involved in the accumulation of l-alanine. d-Cycloserine appears to be primarily transported by the d-alanine-glycine system. The accumulation of d-alanine, glycine, and d-cycloserine was characterized by two line segments in the Lineweaver-Burk analysis, whereas the accumulation of l-alanine was characterized by a single line segment. d-Cycloserine was an effective inhibitor of glycine and d-alanine accumulation, and l-cycloserine was an effective inhibitor of l-alanine transport. The systems were further differentiated by effects of azide, enhancement under various growth conditions, and additional inhibitor studies. Since the primary access of d-cycloserine in E. coli is via the d-alanine-glycine system, glycine might be expected to be a better antagonist of d-cycloserine inhibition than l-alanine. Glycine and d-alanine at 10(-5)m antagonized the effect of d-cycloserine in E. coli, whereas this concentration of l-alanine had no effect.
已发现大肠杆菌中d-丙氨酸、l-丙氨酸、甘氨酸和d-环丝氨酸的积累是由至少两种转运系统介导的。d-丙氨酸和甘氨酸的转运系统相关，且与参与l-丙氨酸积累的系统不同。d-环丝氨酸似乎主要通过d-丙氨酸-甘氨酸系统转运。在Lineweaver-Burk分析中，d-丙氨酸、甘氨酸和d-环丝氨酸的积累表现为两条线段，而l-丙氨酸的积累表现为一条线段。d-环丝氨酸是甘氨酸和d-丙氨酸积累的有效抑制剂，l-环丝氨酸是l-丙氨酸转运的有效抑制剂。通过叠氮化物的作用、在各种生长条件下的增强作用以及其他抑制剂研究，进一步区分了这些系统。由于d-环丝氨酸在大肠杆菌中的主要进入途径是通过d-丙氨酸-甘氨酸系统，因此甘氨酸可能比l-丙氨酸更适合作为d-环丝氨酸抑制作用的拮抗剂。10^(-5)m的甘氨酸和d-丙氨酸可拮抗d-环丝氨酸对大肠杆菌的作用，而该浓度的l-丙氨酸则无作用。
