The vial gives the quantity as "10,000 units", and if the activity is 10,000 units per mg, which your question implies, then you must have 1mg calmodulin in the vial. The concentration will therefore be determined by the volume that you add to dissolve the powder. e.g. If you initially add 950ul of buffer and then make up to exactly 1ml (it's fiddly on this scale, I know) you will have 10000 units per ml. Simply adding 1ml to the vial will be approximately right as the formulation is salt free and little volume expansion of the 1ml would be expected. I cannot quite read the label, but it looks like 98% pure, not 95%? Anyway, you have 2 or 5% of something else, but that does not affect the vial quantity which is given as 10,000 units, a measure of calmodulin, not the 2-5% of contaminants.