Question

How is the gene Z (for $\beta$ galactosidase) used as a marker?

Answer 1

Beta-galactosidase is a useful tool for bacterial genetic engineering. The active sites of beta-galactosidase are formed by four chains, each having $1023$ amino acids (blue). In two of these active sites, the substrate/product allolactose (pink and white) can be seen. The $GLB1$ gene directs the production of an enzyme known as beta-galactosidase (-galactosidase). This enzyme is found in lysosomes, which are cellular compartments that break down and recycle various chemicals.

Complete answer:
The coding sequence of galactosidase is introduced using recombinant DNA, which causes the enzyme to be activated (called insertional inactivation). A chromogenic material is used to treat it. They are recombinants if the plasmid in the bacterium has an insert that produces blue colour, and they are not recombinants if the plasmid in the bacterium does not produce blue colour. Lactose is converted to glucose and galactose by -galactosidase, which is encoded by the lacZ gene. Lactose is transported into the cell by - galactoside permease, which is encoded by the lac Y gene.
Galactosidase is a lactose enzyme that binds galactose and glucose (lactose's two monosaccharides): Galactose is the first subsite. D-galactose is a highly selective substrate for the enzyme.
An exoglycosidase that hydrolyzes the glycosidic bond produced between a galactose and its organic component is known as -galactosidase. It can cleave fucosides and arabinosides as well, though at a considerably slower rate. In the human body, it is a necessary enzyme.

Note:
The buildup of yellow hue (increase $420{\text{ }}nm$ absorbance) each minute is monitored to determine -galactosidase activity. The reaction mixture's $OD420$ and $OD550$ are measured. The cell density in the washed cell suspension is measured by the $OD600$. T is the reaction's time in minutes. In mLs, V represents the volume of culture utilized in the experiment.