Question

which enzyme in the graph has the higher km and affinity? a has a high km but b has a high affinity. b has a high km but a has a high affinity. b has a high km but a has a low affinity. a has a high km but b has a low affinity.

Explanation:

The Michaelis - Menten constant ($K_m$) is the substrate concentration at which the reaction rate is half of the maximum rate ($V_{max}$). A lower $K_m$ value indicates a higher affinity of the enzyme for its substrate. From the graph, when comparing the two enzymes, Enzyme B has a higher $K_m$ (it reaches half - $V_{max}$ at a higher substrate concentration). Enzyme A has a lower $K_m$, which means it has a higher affinity for the substrate.

Answer:

B. Enzyme B has a high $K_m$ but Enzyme A has a high affinity