Here's another question...

I know the formula :

** A=ecl**, and what each symbol stands for, but I don't know where to start.

You are assaying isocitrate dehydrogenase, in which NAD+ is converted to NADH. You have a 20 ml sample of protein, which contains a total of 200mg of protein. You take an aliquot of your solution (10ul) and place it in a 1 cm cuvette, in a total volume of 1 ml. After reading baseline values you add isocitrate, and measure the increase in absorbance at 340nm. The increase is 0.15 absorbance units per minute. If 1 unit of enzyme activity is equal to the production of 1 umole/minute of product, how many total units are there in your starting material? The molar extinction coefficient of NADH is 6.3x10

^{3}.