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.
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.
the Presence of ACE Inhibition
ACE inhibitions is present in the
absorbance of the sample (Total
sample AU – Blank 2 AU)
is lower than Blank 1 (Total Blank
1 AU – Blank 2 AU).
tests unit size, 14 samples can be tested in triplicate
50 (50% inhibitory concentration)
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.
the concentration of the sample solution that gives 50% ACE inhibitory activity
as indicated in Fig. 4 .
tests unit size, 2 samples can be tested in triplicate
1) L. H. Lam, et al., Assay of angiotensin I-converting enzyme-inhibiting activity based on the detection of 3-hydroxybutyric acid. Anal Biochem
2) L. H. Lam, et al., Assay of angiotensin I-converting enzyme-inhibiting activity based on the detection of 3-hydroxybutyrate with water-soluble tetrazolium salt. Anal Sci
3) L. H. Lam, et al., Flow injection analysis of angiotensin I-converting enzyme inhibitory activity with enzymatic reactors. Talanta
4) Hiromichi Nakamura, et al., Antihypertensive Effects of Continuous Oral Administration of Nattokinase and Its Fragments in Spontaneously Hypertensive Rats
. Biol. Pharm. Bull
; 34(11) 1696 E701.
5) C. C. Lau, N. Abdullah and A. S. Shuoib, Novel angiotensin I-converting enzyme inhibitory peptides derived from an edible mushroom,Pleurotus cystidiosus O.K. Miller identified by LC-MS/MS, BMC Complement. Altern. Med
, 13, 313.
6) K. Yamaki, Screening Research Methods for α-glucosidase Inhibitors and Angiotensin-converting Enzyme Inhibitors in Fermented Soybean Products and Fermented Milk Products ,JARQ
, 48, 41.
7) C.Lau, N. Abdullah, A. Shuib, and N.Aminudin, Novel angiotensin I-converting enzyme inhibitory peptides derived from edible mushroom Agaricus bisporus (J.E. Lange) Imbachi identified by LC-MS/MS
, Food Chemistry
, 148, 396-401.
8) R. Nakabayashi, Z. Yang, T. Nishizawa, T. Mori and K. Saito, Top-down Targeted Metabolomics Reveals a Sulfur-Containing Metabolite with Inhibitory Activity against Angiotensin-Converting Enzyme in Asparagus officinalis
, J. Nat. Prod
, 78(5), 1179.
9) M. Alauddin, H. Shirakawa, K. Hiwatashi, A. Shimakage, S. Takahashi, M. Shinbo and M. Komaia, Processed soymilk effectively ameliorates blood pressure elevation in spontaneously hypertensive rats
, J. Funct. Foods
, 14, 126.
10) L. Basirico, E. Catalani, P. Morera, S. Cattaneo, M. Stuknyte, U. Bernabucci, I.De Noni, and A. Nardone, Release of angiotensin converting enzyme-inhibitor peptides during in vitro gastrointestinal digestion of Parmigiano Reggiano PDO cheese and their absorption through an in vitro model of intestinal epithelium
, Journal of Dairy Science
, 98(11), 7595-7601.
11) T. Hagi, M. Kobayashi, and M. Nomura, Metabolome analysis of milk fermented by gamma-aminobutyric acid-producing Lactococcus lactis
, Journal of Dairy Science
, 99(2), 994-1001.