Assessment 2 – Computer Assignment
1. It is desired to find the rate parameters of an enzymatic reaction which is assumed to follow Michaelis-
Menten (M-M) kinetics. There are no inhibitors present and the reaction is not inhibited by the product or
the substrate. The reaction rates at different substrate concentrations were obtained using initial-rate
experiments. These are given in Table 1.
Estimate the rate parameters using linear regression based on the three commonly used linearization of
the M-M rate equation. Also estimate the parameters using non-linear regression. Use Matlab for the
egression analysis. Analyse your results and discuss the uncertainties (e
ors) in the parameters
particularly in terms of the effect of the linearized form that was used to estimate them. Summarise your
conclusions from this analysis.
[S]
(x 10-4 mol/l)
v
(x 10-4 mol/l/s)
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Note: You need to review regression analysis using Matlab. A pdf file containing instructions on how to use
Matlab for regression analysis is provided under Activity 2.2 in Learnline. You also require an understanding
of how to estimate uncertainty in a parameter using propagation of e
ors. A document describing this
technique is also available under Activity 2.2.
2. (Problem 3.13 Kargi and Schuler). The following data was obtained from enzymatic oxidation of phenol
y phenol oxidase at different phenol concentrations.
(a) Determine the type of inhibition mechanism for this reaction.
(b) Determine the Michaelis-Menten parameters and the dissociation constant KI for the inhibitor.
Note: Inhibition can be due to inhibitor present or due to substrate. Use non-linear regression as well as
one of the linearised equations. Choose the linearised equation based either on your observations in the
first problem.
[S] mg/l v (mg/l-h)
10 5.0
20 7.5
30 10.0
50 12.5
60 13.7
80 15.0
90 15.0
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130 9.5
140 7.5
150 5.7
Your submission should be in the form of a report for each of the problem. This report will consist of a
ief
summary including the aim of your work, description of the methodology used, results and analysis
followed by conclusions.
Assessment 2: Marking Scheme
Format, clarity and structure of report 15%
Aims
Procedure adopted
Clarity of graphs, figures
Format
Problem 1: 55%
Implementation: 10% (Linear regression – 5%; Non-linear regression: 5%)
Description of linearization methods and non-linear regression
Estimation of parameters
Results: 15%
Graphs
Tables
Analysis & Conclusions: 30%
Comparison of different linear methods including e
or analysis of parameters (15%)
Comparison of linear and nonlinear methods including e
or analysis of parameters (10%)
Problem 2: 30%
Implementation: 7%
How will inhibition be identified using linear regression? Which type of plot will be used? (8%)
How will the inhibition be identified using non-linear regression? (7%)
Results: 8%
Graphs
Tables
Analysis and Conclusions: 12%
Discussion based on graphs to identify type of inhibition using linear regression (3%)
Discussion based on graphs to identify type of inhibition using nonlinear regression (3%)
Estimation of parameters (9%)