Why is the specificity constant a better measure of enzyme preference at low substrate concentrations compared to kcat alone?

In a laboratory setting, why might studying an enzyme at saturating substrate concentrations not provide an accurate measure of its binding affinity?

What is the significance of a catalytically perfect enzyme in terms of the specificity constant?

Which enzyme would have the highest specificity constant if urease has a kcat of 10,000 s^-1 and Km of 0.01 M, penicillinase has a kcat of 2,000 s^-1 and Km of 0.0001 M, and chymotrypsin has a kcat of 100 s^-1 and Km of 0.001 M?

Given an enzyme with a kcat of 500 s^-1 and a Km of 0.05 M, calculate the specificity constant and explain its significance.

Which enzyme would be considered more efficient at low substrate concentrations if urease has a specificity constant of 3 x 10^7 M^-1 s^-1, penicillinase has 5 x 10^7 M^-1 s^-1, and chymotrypsin has 1 x 10^7 M^-1 s^-1?

Why is the association rate constant k1 important in enzyme kinetics?