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Why is onpg used as the substrate for the β-galactosidase assay rather than lactose?

User Second Son
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Answer:

Step-by-step explanation:

Unlike lactose, the substrate O-nitrophenyl-beta-D-galactopyranoside (ONPG) is capable of penetrating the bacterial cell without the presence of permease. In the broth method of testing, the organism is taken from a medium containing a high concentration of lactose and is inoculated into the ONPG Broth.

User Maria Vill
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