Substrate Concentration $($mM$)$

$40$

Using MS Excel for non$-$linear $($MM$)$ fit is very easy. Enter your $x$ in the column A$.$ Enter your y in the column B$.$ Estimate your criteria approximately from the graph. Enter calculated y $($using appropriate formula with the criteria used$)$ in the column $C.$ Set the square of the difference between $B$ and $C$ values in the column D$.$ Calculate the sum of the column D$.$ Highlight the cell with that sum. Go into Solver menu. If the Solver is not there, load it up by going into Ad$-$Ins. Once you've got into the Solver. Set the target cell to minimize by changing cells that have your criteria in$.$ Run, it takes about $5se{c}^{\text{'}}s$ to do it$,$ and after OK$,$ you get your optimized criteria in the criteria cells. Included is an example of such calculation.