Melkonian L O, Avetisova G E, Ambartsumian A A, Chakhalian A Kh, Sagian A S
Prikl Biokhim Mikrobiol. 2013 Mar-Apr;49(2):144-8. doi: 10.7868/s0555109913020098.
The mechanisms of L-alanine overproduction by Brevibacterium flavum producer strains were studied. It was shown that beta-CI-L-alanine is an inhibitor of some key enzymes involved in the synthesis of L-alanine, including alanine transaminase and valine-pyruvate transaminase. Two highly active B. flavum GL1 and GL1 8 producer strains, which are resistant to the inhibitory effect of beta-Cl-L-alanine, were obtained using a parental B. flavum AA5 producer strain, characterized by a reduced activity of alanine racemase (>or=98%). It was demonstrated that the increased L-alanine synthesis efficiency observed in the producer strains developed in this work is associated with the absence of inhibition of alanine transaminase by the end product of the biosynthesis reaction, as well as with the effect of derepression of both alanine transaminase and valine-pyruvate transaminase synthesis by the studied compound.
对黄色短杆菌生产菌株过量生产L-丙氨酸的机制进行了研究。结果表明，β-氯-L-丙氨酸是参与L-丙氨酸合成的一些关键酶的抑制剂，包括丙氨酸转氨酶和缬氨酸-丙酮酸转氨酶。使用亲本黄色短杆菌AA5生产菌株获得了两种对β-氯-L-丙氨酸的抑制作用具有抗性的高活性黄色短杆菌GL1和GL18生产菌株，其特征在于丙氨酸消旋酶活性降低（≥98%）。结果表明，在本研究中开发的生产菌株中观察到的L-丙氨酸合成效率提高与生物合成反应终产物对丙氨酸转氨酶的抑制作用缺失有关，也与所研究化合物对丙氨酸转氨酶和缬氨酸-丙酮酸转氨酶合成的去阻遏作用有关。
