TABLE 2.
Physiological effects of lacZ, lacA, galA, and yesZ expression in E. coli
| Construct | Enzyme expressiona
|
Hydrolysis or growthb
|
||||||
|---|---|---|---|---|---|---|---|---|
| LacZ | YesZ | LacA | GalA | X-Gal | Galactose | Lactose | Galactan | |
| pΔα18 | − | − | − | − | − | + | − | − |
| PLacZ | + | − | − | + | + | + | − | |
| PLacA | − | − | + | − | + | + | − | − |
| PGalA | − | − | − | + | − | + | − | − |
| pYvfs (pGalALacA) | − | − | + | + | + | + | − | + |
| PGalAYesZg | − | + | − | + | + | + | − | − |
| pGalALacZ | + | − | − | + | + | + | + | − |
a
+, gene for enzyme present; −, gene for enzyme absent.
b
+, hydrolysis detected (hydrolysis of X-Gal determined by formation of blue product and hydrolysis of other compounds determined by growth on M9 media). −, no hydrolysis detected.