Question

When measuring

cat
k
cat
​
, the turnover number of an enzyme, at what substrate concentration is it typically determined?

a) At very low substrate concentrations.

b) At moderate substrate concentrations.

c) At high substrate concentrations.

d) At saturating substrate concentrations.

Answer 1

The turnover number of an enzyme is measured at saturating substrate concentrations, where all enzyme active sites are occupied, reflecting the enzyme's maximum catalytic efficiency.

Step-by-step explanation:

When measuring the turnover number of an enzyme, also known as catk cat, it is typically determined at saturating substrate concentrations. This is the point at which all enzyme active sites are occupied by substrate, and further increase in substrate concentration does not lead to an increase in reaction rate. The turnover number reflects how many substrate molecules are converted to product molecules per unit time when an enzyme is fully saturated with substrate, indicating the maximum catalytic efficiency of the enzyme.