LIBERATION OF SUCROSE-HYDROLYZING ENZYMES FROM CELLS BY THE ZLIS GENE-PRODUCT THAT MEDIATES PROTEIN SECRETION IN ZYMOMONAS-MOBILIS

A 1.7 kb DNA fragment containing both the zliE and zliS genes compleme nts the sucrose-deficiency of the mutant, Z6C-S2, derived from Zymomon as mobilis ATCC 29191, and the mutant containing both genes produces s ucrose-hydrolyzing enzymes extracellularly. The mutant containing zliE accumulates the enzymes within the cells, while that containing zliS does not produce the enzymes (Kondo, T. et al., Biosci. Biotech. Bioch em., 58, 526-530, 1994). In the mutant cells containing zliE, most of the sucrose-hydrolyzing enzymes were bound on the cell surface, and th ese enzymes were liberated when incubated with either washing, suspens ion or extract of the cells containing zliS. These results suggest tha t a product of the zliS gene affects the cell membrane to stimulate th e liberation of cell-associated proteins.