ACE ( Angiotensin Converting Enzyme)
For the quantitative in vitro determination of angiotensin converting enzyme activity in serum.
Angiotensin converting enzyme (ACE), also known as kininase II, is a dipeptidyl carboxypeptidase (EC 3.4.15.1) with a molecular weight of at least 129,000. The structure of this glycoprotein shows a single polypeptide chain, a polysaccharide residue, and a zinc atom. ACE is present in many different cell types such as neuronal cells and renal proximal tubular cells but is mostly found in endothelial cells. It is attached to the endothelial surface membrane by an anchor peptide and can be cleaved to be released into the blood circulation as a soluble enzyme. Serum ACE activity is significantly elevated in patients with the untreated active disease. Spontaneous or corticosteroid-induced remission of sarcoidosis is indicated by decreasing serum ACE values. Only a few patients with lung diseases such as tuberculosis, fibrosis, and tumors, show elevated serum ACE values. Measurement of serum ACE activity is therefore extremely useful as an aid in the diagnosis and in the management of sarcoidosis. The determination of ACE activity in Gaucher’s disease is not used as a screening procedure, but its value is significantly increased in most cases if sarcoidosis can be excluded6.ACE is inhibited by drugs from the family of Captopril. Agents acting through this mechanism are now well established in the treatment of heart failure and hypertension. Serum ACE activity can be a useful parameter for monitoring the effect of these hypotensive drugs inhibiting ACE.
FAPGG → FAP + GG
The decrease in absorbance at 340 nm is directly related to the activity of ACE.
- Ferlitsch, A. et al.: Angiotensin converting enzyme (ACE), a blood test for diagnosis of sarcoidosis. Klin. Wochenschrift 58, 195-198 (1980).
- Baur, X. et al.: Value of angiotensin I – converting enzyme in the diagnosis of sarcoidosis. Klin. Wochenschrift 58, 199 (1980).
- Holmquist B, Bunning P, Riordan JF: A continuous spectrophotometric assay for angiotensin converting enzyme. Anal Biochem , 540 (1979).
- Liebermann, J., Beutler, E.: Elevation of serum angiotensin converting enzyme in Gaucher’s disease. N.Engl. J. Med. 294, 1442-1444 (1976).
- Kamoun, P.P. et al.: Measurements of angiotensin converting enzyme in captopril treated patients. Clin Chim. Acta 118, 333-336 (1982).