Which one of the following statements about Km value is true?: (A) Km is substrate concentration at maximal velocity, (B) Numerical value of km is propoional to affinity of enzyme for substrate, (C) Km is independent of enzyme concentration, (D) Km denotes that 100% of enzyme molecules are bound with substrat molecules at that concentration
Answer is C. Substrate Concentration, A small Km indicates that the enzyme requires only a small amount of substrate to become saturated. Hence, the maximum velocity is reached at relatively low substrate concentrations. A large Km indicates the need for high substrate concentrations to achieve maximum reaction velocity.