What is the Difference Between ACE 1 and ACE 2

The main difference between ACE 1 and ACE 2 is that ACE1 is the central component of the renin-angiotensin system, controlling blood pressure and regulating the fluid volume of the body, whereas ACE 2 occurs attached to the membrane of cells of the kidney, intestine, heart, testis, and gall bladder.

ACE 1 and ACE2 are two types of angiotensin-converting enzymes (ACE) that are the central component of the renin–angiotensin–aldosterone system (RAAS), monitoring the blood pressure of the body.

Key Areas Covered

1. What is ACE 1
     – Definition, Structure, Function
2. What is ACE 2
     – Definition, Structure, Function
3. Similarities Between ACE 1 and 2
      – Outline of Common Features
4. Difference Between ACE 1 and 2
     – Comparison of Key Differences

Key Terms

ACE 1, ACE 2

What is ACE 1

ACE 1 is one of the two isozymes of ACE (angiotensin-converting enzyme). It is a central component of the renin-angiotensin system (RAS). The main function of this system is to control blood pressure by regulating the volume of fluid in the body. Most importantly, ACE 1 converts the hormone angiotensin I into vasoconstrictor angiotensin II, which is the active form. By this, ACE 1 can increase the blood pressure constricting blood vessels. Other known functions of ACE 1 include the breakdown of substance P, bradykinin, and amyloid beta protein.

Figure 1: Renin-Angiotensin System

Furthermore, ACE1 is a zinc metalloproteinase, catalyzing peptide hydrolysis. Due to the critical role of zinc, metal-chelating agents can inhibit ACE 1. On the other hand, ACE 1 is expressed in many tissues, including those in the lungs, vascular endothelial cells, Leydig cells in testicles, sperms, and in epithelial cells in the kidney. In addition, the brain tissue contains ACE 1 involved in the local renin-angiotensin systems. Meanwhile, ACE inhibitors are a class of pharmaceutical drugs important in the treatment of cardiovascular disease. They are important in high blood pressure, heart failure, type 2 diabetes mellitus, and diabetic nephropathy. This type of inhibition is a competitive enzyme inhibition.  

What is ACE 2

ACE 2 is the other isozyme of the enzyme ACE (angiotensin-converting enzyme). It occurs attached to the membrane cells of the kidney, intestine, heart, gall bladder, and testis. It occurs in both membrane-bound and soluble forms. Both types of enzymes are a part of the renin-angiotensin system, keeping blood pressure regulated. The soluble portion of the ACE 2 reduces blood pressure by hydrolyzing angiotensin II, the vasoconstrictor peptide, into angiotensin 1-7, which are vasodilators. Therefore, the process of ACE 2 is important in drug targeting in cardiovascular disease.

Figure 2: ACE 2

Moreover, ACE 2 that occurs in the membranes serves as entry points for the coronavirus. Coronavirus down-regulates the ACE 2. However, structure-wise, ACE 2 is also a zinc-containing metalloprotein.

Similarities Between ACE 1 and ACE 2

• ACE 1 and ACE 2 are two components of the renin–angiotensin–aldosterone system (RAAS).
• Their function is to monitor blood pressure.
• Also, they are isozymes that express in many tissues, including those in the lungs, vascular endothelial cells, testicular Leydig cells, and epithelial kidney cells.
• Besides, both are zinc-containing metalloenzymes.

Difference Between ACE 1 and ACE 2

Definition

ACE 1 refers to a central component of the renin-angiotensin system (RAS), which controls blood pressure by regulating the volume of fluids in the body, while ACE 2 refers to an enzyme that can be found either attached to the membrane of cells in the intestines, kidney, testis, gallbladder, and heart or in a soluble form.

Occurrence

ACE 1 occurs in the lungs, vascular endothelial cells, Leydig cells, epithelial kidney cells, and sperms, while ACE 2 occurs in the membrane cells of the intestines, kidney, testis, gallbladder, and heart.

Importance

Moreover, ACE 1 serves as the central component of the renin-angiotensin system, while ACE 2 attaches to the membrane of many cells.  

Function

ACE 1 undergoes activation of angiotensin II, constricting blood vessels, while ACE 2 undergoes hydrolysis of angiotensin II, dilating blood vessels.

Blood Pressure

Furthermore, ACE 1 increases blood pressure, while ACE 2 decreases blood pressure.

Conclusion                                                     

In brief, ACE 1 and ACE 2 are two types of isozymes, and they are zinc-containing metalloenzymes. Their main function is to be a part of the renin-angiotensin system of the body. They also help in regulating blood pressure and the volume of fluids inside the body. Of these two tpes, ACE 1 is a central component of the renin-angiotensin system. It also occurs in the lungs, vascular endothelial cells, Leydig cells, epithelial kidney cells, and sperm. The main function of ACE 1 is to increase the blood pressure of the body by activating angiotensin 1. Meanwhile, ACE 2 occurs in the membrane cells of the intestines, kidney, testis, gallbladder, and heart. In addition, it attaches to the many cell membranes of the body. However, the main function of ACE 2 is to decrease blood pressure by hydrolyzing angiotensin II. Therefore, the main difference between ACE 1 and ACE 2 is their function.

References:                

1. Yamamoto N, Nishida N, Yamamoto R, Gojobori T, Shimotohno K, Mizokami M, Ariumi Y. Angiotensin-Converting Enzyme (ACE) 1Gene Polymorphism and Phenotypic Expression of COVID-19 Symptoms. Genes (Basel). 2021 Oct 1;12(10):1572. doi: 10.3390/genes12101572. PMID: 34680966; PMCID: PMC8535484.

Image Courtesy:

1. “Renin-angiotensin-aldosterone system” By Soupvector – Own work (CC-BY SA 4.0) via Commons Wikimedia
2. “Protein ACE2 PDB 1r42” By Emw – Own Work (CC-BY SA 3.0) via Commons Wikimedia