ACE and hypertensive disorder: Several of these belong to the renin-angiotensin system (RAS) and the kinin-kallikrein system (KKS), with key relevance to blood pressure regulation and therefore hypertension [28], and has led to the seemingly opposing action of hemorphins on the enzyme angiotensin-converting enzyme (ACE) [14] and angiotensin II (AngII) [29] receptor (AT1R) as well as the bradykinin receptor.