Question

Biochemistry Quiz 2 (Enymes, Catalysis. Vitamins) whe an aldehyde group. How would 1. An encryme converts an alcohol group of you classify this enzyme? a) Transferase b) Ligase c) Oxidoreductase d) Isomerase e) Ketolase 2. Which statement is true about catalysts? a) They are generally complementary to the substrate b) They lower the free energy of the intermediates c) They stabilire transition states. d) They reduced e) All of the above 3. what is meant by the steady-state assumption in the derivation of the Michaelis-Menten equation? a. The concentration of ES is constant b. The formation of the product is the rate-limiting step The reaction has achieved maximum velocity d. The rate of the P E - ES is negligible e. The temperature is constant 4. Which point is the value of K?

Answer 1

1) OPTION C. Every enzyme that catalyzes the forward reaction also has the ability to accommodate the product and catalyze the reverse reaction at the same efficiency. So, an enzyme that oxidizes an alcohol to its aldehyde will also reduce the aldehyde to the corresponding alcohol. Hence, the enzyme that oxidizes an alcohol is classified as an oxidoreductase, with the suffix "-ase" indicating that it is an enzyme.

2) OPTION E. Catalysts are reaction modulators that increase the rate of the reaction by stabilizing the transition state of the reaction, achieved by orienting the substrates in a conformation that facilitates the formation of the activated complex. This way, they also render the formation of the transition state more spontaneous and decrease the Gibbs free energy of the activated complex. In terms of enzymes, the active site of the macromolecule where the substrate binds to the enzyme possesses amino acid residues that possess interactions complementary to the substrate to have specificity for substrate recognition.

3) OPTION A. In chemical kinetics, the steady-state approximation assumes that the rate of formation and disappearance is constant. Extrapolating it to Michealis-Menten kinetics, the final equation it is assumed that the concentration of the E-S complex is constant at the time-frame of the product formation. This is also known as the quasi-steady-state equation.

4) OPTION C. The Michealis-Menten equation considers that the product is formed by the enzyme combining with the substrate first, forming an activated enzyme-substrate complex which then decomposes into the free, active enzyme and the product. In this, Vmax is the maximum rate of reaction.

Km, the Michealis-Menten constant gives the concentration of substrate, at which the reaction velocity is equal to exactly half the maximum velocity attainable by the reaction. It can also be thought as the binding affinity of the substrate to the enzyme.