Cronkite D L, Diekman A B, Lewallen B, Phillips L
Biology Department, Hope College, Holland, Michigan 49422-9000.
J Eukaryot Microbiol. 1993 Nov-Dec;40(6):796-800. doi: 10.1111/j.1550-7408.1993.tb04477.x.
When Paramecium calkinsi encounter hyperosmotic stress, intracellular free alanine increases. In vivo assays indicate that the reaction catalyzed by alanine aminotransferase contributes to the build up of alanine in response to hyperosmotic shock. 14C-pyruvate is converted to 14C-alanine in cells grown axenically at 200 mosm. When shifted to 600 mosm, the rate of conversion of pyruvate to alanine increases, and conversion at either 200 or 600 mosm is blocked by 1 mM aminooxyacetic acid (AOA), an inhibitor of aminotransferase. Intracellular free alanine increase is partially inhibited by AOA, and AOA prevents cells living in fresh water from acclimating to higher salinities, an indication that the increase in intracellular alanine is physiologically significant.
当卡氏草履虫遭遇高渗胁迫时，细胞内游离丙氨酸会增加。体内实验表明，丙氨酸转氨酶催化的反应有助于在高渗休克反应中积累丙氨酸。在200毫渗压浓度下无菌培养的细胞中，14C-丙酮酸会转化为14C-丙氨酸。当转移至600毫渗压浓度时，丙酮酸向丙氨酸的转化速率增加，并且在200或600毫渗压浓度下的转化均被1毫摩尔的氨基氧乙酸（AOA，一种转氨酶抑制剂）所阻断。细胞内游离丙氨酸的增加被AOA部分抑制，并且AOA会阻止生活在淡水中的细胞适应更高盐度，这表明细胞内丙氨酸的增加具有生理意义。
