A pair of isoenzymes, X and Y, were isolated from different tissues within the same organism. Each enzyme catalyses the conversion of the same substrate (S)into the same product (P), both obeying Michaelis-Menten kinetics. (i) Table 1, lists initial rate data for the conversion of S →- P at room temperature in presence of the same (low) concentration of enzyme X. Use a suitable graph plotting program (Graph plotter or an alternative program) to produce a Lineweaver-Burk plot for the data in Table 1. (A copy of the data in Table 1 (CSV format), is provided in the Assessment area of the S315 website.) You should also include a table of your plotted data as part of your answer and include all calculations, taking particular care to include powers of ten and units throughout. (ii) Use the Lineweaver-Burk plot to calculate KM and Jmax. Note: you should use the values of the gradient and intercept from the software fit of the data in your calculations. (b) A similar experimental study of the catalysed conversion of S → P at 25 °C,in the presence of the same (1low) concentration of enzyme Y was carried out. (i) For enzyme Y, the initial rate (Jo) was found to be two-thirds (2/3), of its limiting value, when the initial substrate concentration was [S]0 = 3.04 ×10-2 mol dm-3. Use this information to calculate a value of KM for enzyme Y. Show your reasoning. (ii) State, giving your reasons, which of the two isoenzymes you would expect to occur in tissue that is likely to experience relatively high concentrations of the substrate S. You can assume that the values of Jmaxfor the two isoenzymes are similar to one another. (4 or 5 sentences.)

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