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Item # Unit Size
50 tests (Trial Size)
100 tests

For Research Use Only Products

Angiotensin-Converting Enzyme (ACE) Inhibition Assay
- Colorimetric Microplate Assay Possible
- Possible to Test Multiple Samples at One Time
- Simple Protocol
- No Harmful Organic Solvent Required
- High Reproducibility

Application: Screening of ACE inhibitors

Click Here for How to determine presence of ACE Inhibition and Determination of IC50

Contents of the Kit:
50 tests(A502-05) 100 tests(A502-10)
Substrate buffer 1 mL x 1 1 mL x 2
Enzyme A 1 tubes 2 tubes
Enzyme B 1 tubes 2 tubes
Enzyme C 1 tubes 2 tubes
Coenzyme 1 tubes 2 tubes
Indicator solution 5 mL x 1 5 mL x 2

Storage Condition: 0-5°C
Shipping Condition: ambient temperature

Required Equipment and Materials
plate reader with 450 nm filter; 96-well culture plate, 2-20 μl, 20-200 μl, 100-1000 μl and multi-channel pipettes; 37ºC incubator, Disposable syringe (1 ml)


Product Description

The kit is used for the determination of ACE inhibition activity. ACE works in the Renin-Angiotensin system, which is one of the mechanisms of blood pressure control, to convert Angiotensin I to the vasopressor Angiotensin II. This enzyme also contributes to elevated blood pressure due to its role in breaking down the antihypertensive peptide Bradykinin. In recent years, food and supplements containing ingredients that block ACE have received attention for their use in preventing high blood pressure. The conventional method of measuring ACE inhibition employs the synthetic substrate Hippuryl-His-Leu. Hippuric acid from the synthetic substrate is extracted with ethyl acetate, condensed, redissolved, and then read at an absorbance of 228 nm. This method is cumbersome and measurement is subjected to error due to residual ethyl acetate. ACE inhibition Assay Kit enzymatically detects 3-Hydroxybutyric acid (3HB), which is made from 3-Hydryoxybutyryl-Gly-Gly-Gly (3HB-GGG). Using a 96-well format, it is possible to test multiple samples at one time. In addition, there is no need to use harmful organic solvents, resulting in a safe, simple, and highly reproducible assay.

Fig. 1
Principle of the assay system to determine ACE activity or inhibition activity.

Get Measurements in Just 2 Hours

In Comparison to Method by Ethyl Acetate


Example Assay Data

Fig. 2 Inhibition curves prepared by Alacepril and Captopril.
IC50 of Alacepril and Captopril are 3.62 μM and 2.14 nM, respectively. Both compounds are ACE inhibitors.

Fig. 3 Inhibition curves prepared by two beverages containing a valyltyrosine () or lacto tripeptide () .
IC50 of these beverages are 0.56% and 0.69%, respectively. It is known that these substances have antihypertensive effects.
*Concentration of the beverage in the sample solution.

Checking the Presence of ACE Inhibition

ACE inhibitions is present in the sample if
absorbance of the sample (Total sample AU – Blank 2 AU)
is lower than Blank 1 (Total Blank 1 AU – Blank 2 AU).

For 50 tests unit size, 14 samples can be tested in triplicate

Determination of IC 50 (50% inhibitory concentration)

Prepare an inhibit ion curve using the sample concentration for X axis and the ACE inhibitory activity for Y axis. A typical inhibition curve is shown in Fig. 4.

Determine the concentration of the sample solution that gives 50% ACE inhibitory activity as indicated in Fig. 4 .

For 50 tests unit size, 2 samples can be tested in triplicate

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