Question

I. Essay Question Answer the following question. Write the number of the question and then your answer. 1. The enzyme A was assayed under the optimal conditions and the following velocity data were obtained: UM nmol/L /min 0.05 0.12 40.4 61.2 10 2.5 40 4.2 Assume Vmax for the enzyme to be 4.5 nmol/L/min Determine: a whether it follows Michaelis-Menten kinetics or not: determine the type of cooperativity (from saturation plot) and from the Koshland coefficient b. determine from the appropriate plots, Km, or Kd' and Hillco

Answer 1

Sole Given the Velocity 1. The Enzyme A was assayed under Optimal Conditions and the following data nmol/e/min o 0.05 0.13 EO-656 0.4 1.2 2.5 4 4.2. 40 4.5-1 Reaction velocity 25 0 5 10 15 20 25 30 35 40 45 Concentration

Vmax for the Enayme to be 4.5 nmol/2/min, as The plot of Reaction velocity against Concentration, gives a Sigmoidal Cs- Shaped Coove). -> Which is Charecteristic of a non- Michaelisa Menten Model. → The S-shaped Curve (sigmoidal) Kinetic Shows a positive - Co-operative binding. o from the Michaelis - Menten plot, The Concentration required for attaining half of the maximum Peaction velocity can be Calaulated. Km value km qul M Hill Co-Efficient = - log (81) NH2 193 % (€ /eco) Relationship between Hill Coefficien, Eclo and Ecao

Where Ecao and Ecio are the input values needed to produce the 90% and 10% of the maximal Activity. Substituing the values in the above equation According to logarithm laws. Tog 81 = 1.9084 Hill Coefficient