Collect. Czech. Chem. Commun. 1986, 51, 2280-2284

Comments on spectrofluorometric assay of angiotensin-converting enzyme activity in blood plasma of different species

Assia C. Shishevaa, Ognian C. Ikonomovb and Luben M. Sirakova

a Department of Chemistry and Biochemistry, Medical Academy, Sofia 1431, Bulgaria
b Department of Physiology, Medical Academy, Sofia 1431, Bulgaria


The activity of the angiotension -converting enzyme (ACE) in human, dog, rabbit, and rat blood plasma was assayed by spectrofluorometric determination of the product liberated by enzymatic cleavage (L-His-L-Leu). In parallel experiments the hydrolysis of L-His-L-Leu by blood plasma was examined. The hydrolytic activity of rat blood plasma was high and therefore lower values of ACE activity were obtained; the use of the spectrofluorometric assay with rat blood plasma is therefore problematic. By contrast, L-His-L-Leu was not degraded by human, dog, and rabbit blood plasma and the spectrofluorometric determination of this peptide can thus be used to advantage to assay the ACE activity of blood plasma samples of these species.