L-异亮氨酸和甘氨酸对大肠杆菌表达与分泌邻苯二酚2,3-双加氧酶的作用

EFFECT OF L-ISOLEUCINE AND GLYCINE ON CATECHOL 2,3-DIOXYGENASE EXPRESSION AND EXCRETION IN ESCHERICHIA COLI

证实了甘氨酸与L-异亮氨酸对大肠杆菌表达邻苯二酚2,3-双加氧酶(CatO_2ase)的促进作用和甘氨酸促使该酶分泌至胞外培养基中的作用.产酶量高低和分泌量多少与培养基种类、甘氨酸和L-异亮氨酸的浓度以及培养时间等因素有关.在甘氨酸存在的情况下,胞壁对溶菌酶的敏感性有所增加,超微形态似有变化,还存在其他物质的伴随分泌,故甘氨酸可能是引起细胞壁结构的改变而导致邻苯二酚2,3-双加氧酶等胞内容物被动分泌至胞外.

The secretion of gene products expressed in E. coli is a problem noticeable nowadays. Effect of glycine and L-Isoleucine on catechol 2,3-dioxygenase (CatO2ase) expression and secretion was reported here. Both L-Ile and Gly could increase CatO2ase production, Gly could also cause expressed product excreted into the culture medium. The effect of Gly and L-Ile was related to the composition of culture medium, the concentration of Gly and L-Ile and the culture time. The sensitivity to lysozyme of bacterium cells grown in the Gly containing medium was a little higher and electron microgragh of bacteria grown in Gly-containing medium showed morphological changes of cell wall and outer memberane. This may have been due to interference with peptidoglycan synthesis by the Gly. and cause passability increase, as reported in other bacterium strains .