Final answer:
Mixed type inhibitors affect both Km and Vmax because they can bind to the enzyme, changing its affinity for the substrate and limiting its maximal reaction rate, even when the active site is fully occupied by the substrate. The correct answer is 5) 'both choices A and B'.
Step-by-step explanation:
Mixed type inhibitors will affect Km (Michaelis constant) and Vmax (maximum rate) of an enzymatic reaction. These inhibitors can bind to the enzyme with or without the substrate being present, and their binding impacts both the affinity of the enzyme for the substrate and the maximum rate at which the product is formed. Therefore, the correct answer is 'both choices A and B'.
Enzyme kinetics play a significant role in understanding how substances can regulate enzyme action. A mixed type inhibitor is unique because it does not merely compete with the substrate; it can also bind to the enzyme at a different site. This binding alters the shape of the enzyme, which can affect the enzyme's activity even when the active site is not directly blocked. The Vmax is reached when all enzymes' active sites are saturated by the substrate. Mixed type inhibitors affect Vmax as they can prevent the enzyme from functioning at full capacity, even when all active sites are bound to substrates. Similarly, Km reflects the affinity of the enzyme for the substrate, and mixed type inhibitors can change this affinity, thus altering the Km value.