# How to Make a Double Reciprocal in Excel

A double-reciprocal graph is a graph where the values on both axes are the reciprocals of the actual data. Double-reciprocal is a synonym for a Woolf-Lineweaver-Burk plot. The plot describes how quickly an enzyme converts its substrate to its output. On the x-axis is the reciprocal of the concentration of the substrate. On the y-axis is the reciprocal of the speed at which the enzyme can consume the substrate concentration. Use Microsoft Excel to graph a double-reciprocal plot.

#### Step 1

Type "S," "V," "1/S" and "1/V" into cells A1, B1, C1 and D1, respectively.

#### Step 2

Type values for "S," the enzyme concentration, in column A, beginning with cell A2. For example, type the numbers one through 10 into cells A2 through A11.

#### Step 3

Type values for "V," the speed of substrate consumption, in column B, beginning with cell B2. For example, type the numbers 11 through 20 into cells B2 through B11.

#### Step 4

Type "=1/A2" into cell C2. Copy that cell and paste it in cells C3 through C11.

#### Step 5

Type "=1/B2" into cell D2. Copy and paste it into cells D3 through D11 as well.

#### Step 6

Select cells C1 through D11.

#### Step 7

Click the "Insert" menu. Click "Scatter," Click "Scatter with Smooth Lines and Markers," the top-right graph option. A double-reciprocal plot will appear.