This K two is also known as K cat and this is given the name of the turnover number of the enzyme. So what exactly is the physiological meaning of the turnover number K two of an enzyme? Well, the turnover number tells us the maximum number of the substrate molecules that are transformed into the product molecules by a single active side per given unit of time. So basically, let's suppose we have a single particular type of enzyme that we're studying and this is our enzyme. It could be any type of enzyme found inside our body. So the enzyme, it's active side.