So the classically units are micromoles per minute which is equal to a unit. But nowadays we also use moles per second. So what the enzyme activity tells us is how many milli or how many micromoles of that product that is produced by the enzyme per minute or how many micro moles of the substrate is transformed by that enzyme every single minute. Now, what about the specific activity? Well, the specific activity is simply the ratio of the enzyme activity to the total protein. So the units are unit per milligram are the units of the specific activity or micromol per minute per milligram, are the units of specific activity?