Ace

Acronym for angiotensin converting enzyme. Course parameter for the assessment of the disease activity of a sarcoidosis. ACE is elevated in sarcoidosis, hyperthyroidism, HIV infection, chronic lung diseases, plasmacytoma, storage diseases, among others. ACE is present in the pulmonary circulation in particularly high concentrations.

Enzyme that belongs to the group of angiotensins (peptide hormones). These are tissue hormones of the renin-angiotensin-aldosterone system. ACE is of great importance for the maintenance of blood pressure and for the regulation of the water-electrolyte balance (see also Kallikrein).

ACE has the properties of a peptidase and converts within the renin-angiotensin system the peptide and prohormone angiotensin I (probably biologically inactive decapeptide) into the hormone angiotensin II. This hormone has a strong vasoconstrictive effect. In this way, ACE indirectly increases blood pressure.

Consequently, ACE inhibitors (these inhibit competitively ACE) are used extensively in the treatment of arterial hypertension.

Furthermore, ACE cleaves substance P (see pruritus below), beta-endorphins and other peptides that modulate the functions of Langerhans cells and T-lymphocytes (inhibiting influence on the contact allergic reaction!).

The ACE polymorphism is an "insertion/deletion" (I/D) polymorphism. The circulating amount of enzyme is small in the I polymorphism. There is apparently an increased risk of contact allergies in carriers of this polymorphism.

The ACE standard value: 8-28 mU/ml.

1. Schnuch A (2013) Genetics of contact allergy. dermatologist 62: 732-738