Colorimetric assays are commonly used to detect enzymatic activity by measuring changes in color or absorbance of a chromogenic substrate. However, ACE2 (Angiotensin-converting enzyme 2) is a membrane-bound enzyme that cleaves peptide substrates, and there are several reasons why a colorimetric assay for ACE2 activity may not be feasible or effective:

1. Substrate specificity: ACE2 has a high substrate specificity and cleaves a limited number of peptide substrates. This specificity can make it difficult to design a colorimetric substrate that is specific for ACE2 and does not cross-react with other enzymes.

2. Membrane-bound enzyme: ACE2 is a transmembrane protein, which can make it difficult to access and assay its activity. Membrane-bound enzymes often require specialized sample preparation and assay techniques that may not be compatible with colorimetric assays.

3. Low activity: ACE2 has relatively low enzymatic activity compared to other enzymes, which can make it challenging to detect activity using colorimetric assays that require a high level of sensitivity.

4. Conformational changes: The enzymatic activity of ACE2 is influenced by its conformational changes, which can be affected by various factors such as temperature, pH, and inhibitors. These changes can affect the accuracy and reproducibility of colorimetric assays.

Overall, the combination of substrate specificity, membrane-bound nature, low activity, and conformational changes makes it difficult to develop a reliable and specific colorimetric assay for ACE2 activity. Alternative methods, such as fluorescent or luminescent assays, may be more suitable for measuring ACE2 activity.

There are colorimetric methods as well:

H M Neels, M E van Sande, S L Scharpé, Sensitive colorimetric assay for angiotensin converting enzyme in serum., Clinical Chemistry, Volume 29, Issue 7, 1 July 1983, Pages 1399–1403, https://doi.org/10.1093/clinchem/29.7.1399

Elased, K. M., Cunha, T. S., Marcondes, F. K., & Morris, M. (2008). Brain angiotensin‐converting enzymes: role of angiotensin‐converting enzyme 2 in processing angiotensin II in mice. Experimental physiology, 93(5), 665-675.

Niti Sharma No, there is not. You mention the homology enzyme. ACE has colorimetric method,but ACE2 has not.