Quantification of Lactase Inhibition

LACTASE INHIBITION
Adapted from the A-Levels thesis of Mireille Captieux, London
This page can be found at www.science-projects.com/LacInhibQuant.htm

Quantitative Procedure

The stoichiometry of this reaction avails itself nicely to following the progress of the reaction, with and without the galactose inhibitor, spectrophotometrically at 420 nm. The primary difference between the following study from that of the previous qualitative protocol of galactose inhibition of lactase is that only one tube is made at a time in this quantitative study. Namely:

Adjust your warmed-up spectrophotometer to 420 nm.

While that is happening, print out this diagram of the protocol, and then follow it using the same recipes for lactase (enz) and saturated galactose.

You will next want to do some graphing to determine which type of inhibition is exhibited by galactose. Some basic thoughts on how to do this is given in another page on enzyme kinetics