<prompt> Which one of the following about enzymes is true?High Km-High affinityLow Km-High affinityNon-competitive inhibition- Decreases KmNon-competitive inhibition Increased Km  <response>: Refer: DM Vasudevan, Textbook of Biochemistry, 7th edition, pg no: 59 - 60The Michaelis constant kmKm provides a measure of the affinity of the enzyme for its substrate.It is equal to substrate concentration at which reaction velocity is equal to 12 Vmax.Km substrate concentration when reaction velocity is Vmax.Km is constant for any given enzyme.Km is independent of substrate or enzyme concentration.The higher is KM, the higher is the concentration of the substrate required to reach 12 Vmax.That is: at a lower affinity, a higher concentration of substrate is required to reach 12 Vmax. Km affinity. 