Baker H, Frank O, DeAngelis B, Baker E
Department of Preventive Medicine and Community Health, New Jersey Medical School, Newark.
Int J Vitam Nutr Res. 1991;61(4):319-24.
Because cycloleucine (CL) inhibits methionine, and probably B12, we studied CL activity in some B12 or methionine dependent microorganisms to determine whether methionine or other amino acids are targeted by CL. We found that branched-chain amino acids, valine in particular, effectively annulled CL growth inhibition, whereas B12 was ineffective. alpha-Ketoisovalerate was the only intermediate in pathways of branched-chain amino acids catabolism that overcome CL toxicity; propionate, methylmalonate, succinate, alpha-ketoisocaproate and alpha-ketoglutarate were inactive by themselves or in combination. This study suggests that CL antagonizes the action of not only B12 and methionine but also branched-chain amino acids. Results seem comparable to those with B12-deficient fruit bats having neurologic involvement.
由于环亮氨酸（CL）会抑制蛋氨酸，可能还会抑制维生素B12，我们研究了CL在一些依赖维生素B12或蛋氨酸的微生物中的活性，以确定CL的作用靶点是蛋氨酸还是其他氨基酸。我们发现，支链氨基酸，尤其是缬氨酸，能有效消除CL对生长的抑制作用，而维生素B12则无效。α-酮异戊酸是支链氨基酸分解代谢途径中唯一能克服CL毒性的中间产物；丙酸盐、甲基丙二酸、琥珀酸盐、α-酮异己酸和α-酮戊二酸单独或联合使用均无活性。这项研究表明，CL不仅拮抗维生素B12和蛋氨酸的作用，还拮抗支链氨基酸的作用。研究结果似乎与患有神经病变的维生素B12缺乏果蝠的情况相当。
