In: Chemistry
suppose you dissolved 2000 U of enzyme in 1 ml of buffer. you take a 20 microlitre of diluted enzyme and add it to 1 ml of substrate solution with a concentration of 0.5mM. how long would it take to covert all of the substrate in the solution? ( assume ideal conditions)
1 unit enzyme is equal to “” the amount of enzyme that catalyzes 1 micromole substrate into product in 1 minute”.
Final concentration of enzyme after dilution = 2000 U per 1 mL buffer
= 2000 U / 1000 microL
= 2 U/ microL
Amount of enzyme in 20 microL aliquot = 20 microL x (2 U/ microL) = 40 U
Substrate concentration = 0.5mM
That is 0.5 mmoles in 1 mL.
Thus, total amount of substrate = 0.5 mmoles
= 500 micromoles [1 mmol = 1000 micromole]
Time (in minutes) required for catalysis = amount of substrate / enzyme unit
= 500 micromoles / 40 units
= 500 micromoles / (40 micromoles per minute)
= 12.5 minutes.