Optimum pH is the suitable pH at which rate of enzyme action is maximum. Different Enzyme function at different pH in human body. Such as pepsin works at 2.00 pH in human body while Salivary amylase works at 6.80. This prevents the different enzyme to work at different places and thus prevents the side effects of different enzymes. This is the exact way of working of different enzyme in our body.
There are lots of different types of enzymes in our body. The one's you really need to know are pepsin, trypsin, lipase, lactase, maltase and sucrase. All of these enzymes function optimally at 37 degrees Celcius, which most other enzymes also function at. But their optimum pH is different, respectively, its: 2.0, 8.0, 4.0, 6.0, 5.0, 6.2. Other than that, the amount of substrate should be about 1.5 times the amount of enzymes and co-enzymes should be present. In the case of lipase, the lipids should already have been emulsified.
There are a number of enzymes in human body and all of them require different criteria for the optimal activity. I am talking generally about it and basically the optimum activity is affected by Temperature of body, PH value of body and some other factors. You can take the example of the experiment that was carried out to check the optimum activity level of pyrethroid-cleaving enzymes in human serum. For getting the complete results of the experiment check out the link. You can analyze the effect of various conditions on the optimum activity of enzymes from the given example. Pyrethroid-cleaving enzymes experiment
You have many different enzymes in your body, that do different jobs in different locations, for that reason each are suited to different optimum conditions...
The main factors that affect an enzymes activity are temperature and PH. Most enzymes in the human body work at an optimum temperature of around 37 degrees celsius, as this is the core body temperature. However PH varies. For example some enzymes like a fairly neutral/lightly acidic PH around 5 or 6, but others for example a digestive enzyme called pepsin which works in the stomach, needs a very acidic PH of around 2 to function at optimum efficiency.
