Which term refers to the specific affinity with which enzymes bind to substrates?

The term that describes the specific affinity with which enzymes bind to substrates is Km, or the Michaelis constant. Km represents the substrate concentration at which the reaction rate is half of Vmax, the maximum velocity of the enzyme-catalyzed reaction. A lower Km value indicates a higher affinity between the enzyme and the substrate, meaning that the enzyme can achieve half-maximum velocity at a lower concentration of substrate. Conversely, a higher Km value signifies a lower affinity, as a higher substrate concentration is required to reach half of the maximum reaction rate.

Understanding Km is vital because it provides insight into how effectively an enzyme can convert substrate into product, which is crucial in many biological processes and applications. It allows researchers to compare the affinities of various enzymes for their substrates under specific conditions, making it a fundamental concept in enzyme kinetics.