You can plot the standard deviation after fitting with the Enzyme Kinetics App. Select the Fitted Report tab in the worksheet and open the embedded graph.
Right Click on the number 1 in the left corner of the graph and select Layer Contents...
With the Layer Contents Dialog box open you can select the Error column in your worksheet and add it to the Graph Layer by selecting the Arrow Button. Select Apply.
You can Edit the Error bars by double clicking the Graph and opening the Plot Details dialog.
Make sure that your column filled with the standard deviation is set to y or x error.