Five reaction mixtures containing 0.50 mg of an enzyme are made up with five different substrate concentrations and the initial rates of the reactions were measured. After data analysis, it was determined that the Km was 32 mM and the Vmax was 120 mmol/min.
a) If the molar mass of the enzyme is 140,000 g/mol, what is the Kcat for the enzyme? Is the enzyme catalytically perfect?
b) Suppose the experiment were repeated with five times the amount of enzyme. How would Km and Vmax be affected?
c) A poison is added to the reaction mixture that is known to bind the enzyme at a site different from where teh substrate binds. The poison and the substrate can bind the enzyme simultaneously but the poison prevents the formation of product. Qualitatively, how would the poison affect Km and Vmax?