Papaya leaves contain some truly unique enzymes that are used primarily for breaking down proteins. As a result, in South American cooking, it's common to see meat wrapped in papaya leaves to tenderize the fibers and break the meat down. The main enzyme that is responsible for this is called papain and is found only in the leaves, not the fruit of the papaya. When papaya tea is made, it will usually be made from the leaves. It's important to understand what papain does in order to grasp why tea made with it can have such a strong impact on certain health conditions, mainly stomach disorders.