Method for measuring the activity of angiotensin converting enzyme in biological samples
AssigneeB.M.R.A. Corporation B.V.
InventorsHans R. Brunner, Jurg Nussberger
Life of this patent
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Abstract
The activity of angiotensin converting enzyme (ACE) is measured in biological samples as body fluids. ACE-activity is estimated in minimally diluted specimens, using the natural substrate angiotensin I at close to physiological concentration. Femtomoles of generated angiotensin II are trapped by specific high affinity monoclonal antibodies and thus protected from degradation by angiotensinases during the incubation step. The same antibodies are subsequently used for quantitation by radioimmunoassay.
Claims18
A method for measurement of the enzyme activity of angiotensin converting enzyme (ACE) in a biological sample on the basis of cleavage of a substrate by ACE and detecting one of the products cleaved from the substrate, characterized by (a) adding angiotensin I (Ang I) as a substrate of ACE to the biological sample, thereby resulting in cleavage of the Ang I to produce Angiotensin II (Ang II), and (b) adding antibodies of a specific affinity for Ang II to the biological sample, and then (c) trapping and protecting by said antibodies the Ang II generated from the cleavage by ACE of Ang I, and then (d) using the same antibodies for quantitation of Ang II by radioimmunoassay.
A method of measuring the in vitro activity of angiotensin converting enzyme (ACE) in a sample of human blood to produce a result that is virtually identical to the corresponding in vivo ACE activity of the sample, comprising:
- (a) withdrawing the sample from a human being into a collection device containing a renin inhibitor and a non-inhibiting anti-coagulant;
- (b) mixing the sample with a predetermined amount of angiotensin I (Ang I) and an angiotensinase inhibitor, resulting in cleavage of the Ang I to produce angiotensin II (Ang II);
- (c) adding antibodies of a specific affinity for Ang II to the sample;
- (d) trapping and protecting the resulting Ang II by the antibodies;
- and
- (e) using the same antibodies for quantitation of Ang II by radioimmunoassay.
A method of measuring the in vitro activity of angiotensin converting enzyme (ACE) in a sample of human blood, wherein the method is able to detect ACE activity to about zero fmol/ml/min, comprising:
- (a) withdrawing the sample from a human being into a collection device containing a renin inhibitor and a non-inhibiting anti-coagulant;
- (b) mixing the sample with a predetermined amount of angiotensin I (Ang I) and an angiotensinase inhibitor, resulting in cleavage of the Ang I to produce angiotensin II (Ang II);
- (c) adding antibodies of a specific affinity for Ang II to the biological sample;
- (d) trapping and protecting the resulting Ang II by said antibodies;
- and
- (e) using the same antibodies for quantitation of Ang II by radioimmunoassay.
Dependencies are inferred from the claim text.