In this article, we will plot a Michaelis Menten graph in Excel using the Michaelis Menten equation. Generally, this equation is used to analyze the kinetic data of enzymes, as it explains the effect of substrate concentration on enzymes. in addition to plotting a graph from the equation, we’ll demonstrate how to extract the value of the Michaelis Menten constant.

## What Is Michaelis Menten Graph?

In the Michaelis Menten graph, we plot the Reaction Velocity (V) on the Y-axis and the Substrate Concentration ([S]) on the X-axis. The graph follows the equation below:

`V = (Vmax*[S])/([S]+Km)`

It is a zero-order equation.

Here,

**V** = Initial velocity of reaction

**Vmax** = Maximum velocity of reaction

**[S]** = Concentration of Substrate

**Km** = Michaelis Menten Constant

At low substrate concentration, the equation becomes:

`V = (Vmax*[S])/Km`

It is a first-order equation.

## Plotting a Michaelis Menten Graph in Excel

To explain the steps, we will use a dataset that contains Substrate Concentration, [S]. We will calculate the Reaction Velocity (V) with the Michaelis Menten equation. We will use educated values of Km and V-max, then find the value of Km and V-max using the observed and calculated Velocity.

### STEP 1 – Insert Michaelis Menten’s Constant and V-max Values

Let’s insert educated values of **Km **and **V-max**.

- Let the values of
**Km**and**V-max**be**10**. - Here, we have inserted
**10**in both Cell**F4**and Cell**F5**.

**Read More: **How to Plot Time Series Frequency in Excel

### STEP 2 – Calculate Value of Initial Velocity

Now we can calculate the value of the initial velocity, using the Michaelis Menten’s equation.

- Select Cell
**C5**and type the formula below:

`=($F$5*B5)/(B5+$F$4)`

Here, Cell **F5 **contains **Km**, Cell **F4 **stores **V-max**, and Cell **B5 **stores the **Substrate Concentration** **[S]**.

- Press
**Enter**and drag the**Fill Handle**down.

As a result, you will see the **Velocity **corresponding to the **Concentration**.

**Read More: **How to Make a Time Series Graph in Excel

### STEP 3 – Plot Michaelis Menten Graph with Calculated Velocity

To plot the graph, you need to select the values of **Concentration **and corresponding **Velocity**.

- Select the range
**B4:C14**.

- Go to the
**Insert**tab and click on the**Insert Scatter**icon.

A drop-down menu will appear.

- Select
**Scatter with Smooth Lines and Markers**option from the drop-down menu.

As a result, you will see the plot on the sheet.

After changing the axis and chart titles, the graph will look like the picture below.

**Read More: **How to Plot Semi Log Graph in Excel

### STEP 4 – Determine Initial Velocity Along with Observed Velocity

- In
**STEP 2**, we calculated the initial velocity with a formula. In that case, we didn’t have absolute values of**Km**and**V-max**. Also, there was no observed velocity. - If you have
**Observed Velocity**like in the dataset below, you can calculate the initial velocity as well as the values of**Km**and**V-max**.

- Select Cell
**D5**and type the formula below:

`=($C$17*B5)/(B5+$C$16)`

- Press
**Enter**and drag the**Fill Handle**down.

### STEP 5 – Find the Difference Between Observed and Calculated Velocities

Having calculated velocity with the Michaelis Menten equation, let’s find the difference between the observed and calculated velocities.

- Select Cell
**E5**and enter the formula below:

`=C5-D5`

- Press
**Enter**and drag down the**Fill Handle**to see the results.

**Read More:** How to Plot Sieve Analysis Graph in Excel

### STEP 6 – Find the Sum of Squares of the Differences

To find the best values for **Km **and **V-max**, we need to determine the sum of squares of the differences.

- Select Cell
**E17**and enter the formula below:

`=SUMSQ(E5:E14)`

Here, we have used the **SUMSQ **function to calculate the summation of squares of the differences.

- Press
**Enter**to see the result.

To obtain the best values for **Km **and **V-max**, the **Sum of Squares of Differences** must be the minimum.

**Read More:** Make a Lineweaver Burk Plot in Excel

### STEP 7 – Plot Michaelis Menten Graph with Both Observed & Calculated Velocities

- Select the range
**B4:D14**.

- Go to the
**Insert**tab and click on the**Insert Scatter**icon.

A drop-down menu will appear.

- Select the
**Scatter with Smooth Lines and Markers**option from the drop-down menu.

As a result, you will see the graph of both **Observed **and **Calculated **velocities.

### STEP 8 – Find Michaelis Menten’s Constant and V-max

To find **Km **and **V-max **for the observed values, we need to calculate the minimum value of the sum of squares of the differences.

For that purpose, we’ll use the **Solver Add-in**.

- Go to the
**Data**tab and click on the**Solver**option from the**Analysis**section.

- In the
**Solver Parameters**box, enter the cell that contains the value of**Sum of Squares of Differences**in the**Set Objective**field. In our case, that is Cell**E17**. - Select
**Min**. - Enter the cells that contain the values of
**Km**and**V-max**in the “**By Changing Variable Cells**” field. - Here, we have typed
**$C$16:$C$17**. - Click
**Solve**to proceed.

- Click
**OK**to proceed.

The desired results will be returned like in the picture below.

### STEP 9 – Insert Half V-max Value in Graph

- To insert the
**Half V-max**value, you need to create a chart like the picture below. - Here, Cell
**B20**stores**0,**while Cell**B21**and Cell**B22**store the value of**Km**. - Cell
**C20**and Cell**C****21**contain the**Half V-max**value. That means,**C17/2**and Cell**C22**stores**0**.

- After creating the
**Half V-max**table, select the graph and**right**–**click**on it.

A menu will appear.

- Click on the
**Select Data**option from this menu.

- Select
**Add**from the**Select Data Source**box.

- Select the
**Series Name**,**X-values**, and**Y-values**. - Here, Cell
**19**is the**Series Name**, the range**B20:B22**is the**X-values**, and the range**C20:C22**is the**Y**–**values**. - Click
**OK**.

- Click
**OK**in the**Select Data Source**box.

As a result, you will see a graph like the picture below.

### STEP 10 – Change Series Chart Type

Let’s change the chart type for the **Half V-max **value graph.

- Select the
**Half V-max**value graph first and**right**–**click**on it.

A menu will appear.

- Select
**Change Series Chart Type**.

- In the
**Change Chart Type**box, change the**Chart Type**to**Scatter with Straight Lines and Markers**. - Click
**OK**.

### Final Output

At the end of this process, you will get the desired point where **Km **is **9.1****15 **and **V-max **is **7.328**.

**Download Practice Workbook**

**<< Go Back To How to Create a Chart in Excel | Excel Charts | Learn Excel**