Angiotensinogen
https://www.uniprot.org/uniprot/P01019
Essential component of the renin-angiotensin system (RAS), a potent regulator of blood pressure, body fluid and electrolyte homeostasis.
Angiotensin-2:
acts directly on vascular smooth muscle as a potent vasoconstrictor, affects cardiac contractility and heart rate through its action on the sympathetic nervous system, and alters renal sodium and water absorption through its ability to stimulate the zona glomerulosa cells of the adrenal cortex to synthesize and secrete aldosterone.
Angiotensin-3:
stimulates aldosterone release.
Angiotensin 1-7:
is a ligand for the G-protein coupled receptor MAS1. Has vasodilator and antidiuretic effects. Has an antithrombotic effect that involves MAS1-mediated release of nitric oxide from platelets.
Post-translational modificationi
Beta-decarboxylation of Asp-34 in angiotensin-2, by mononuclear leukocytes produces alanine. The resulting peptide form, angiotensin-A, has the same affinity for the AT1 receptor as angiotensin-2, but a higher affinity for the AT2 receptor.1 Publication
In response to low blood pressure, the enzyme renin/REN cleaves angiotensinogen to produce angiotensin-1. Angiotensin-1 is a substrate of ACE (angiotensin converting enzyme) that removes a dipeptide to yield the physiologically active peptide angiotensin-2. Angiotensin-1 and angiotensin-2 can be further processed to generate angiotensin-3, angiotensin-4. Angiotensin 1-9 is cleaved from angiotensin-1 by ACE2 and can be further processed by ACE to produce angiotensin 1-7, angiotensin 1-5 and angiotensin 1-4. Angiotensin 1-7 has also been proposed to be cleaved from angiotensin-2 by ACE2 or from angiotensin-1 by MME (neprilysin).2 Publications
The disulfide bond is labile. Angiotensinogen is present in the circulation in a near 40:60 ratio with the oxidized disulfide-bonded form, which preferentially interacts with receptor-bound renin.
Angiotensin-converting enzyme 2
https://www.uniprot.org/uniprot/Q9BYF1
Essential counter-regulatory carboxypeptidase of the renin-angiotensin hormone system that is a critical regulator of blood volume, systemic vascular resistance, and thus cardiovascular homeostasis (PubMed:27217402).
Converts angiotensin I to angiotensin 1-9, a nine-amino acid peptide with anti-hypertrophic effects in cardiomyocytes, and angiotensin II to angiotensin 1-7, which then acts as a beneficial vasodilator and anti-proliferation agent, counterbalancing the actions of the vasoconstrictor angiotensin II (PubMed:10969042, PubMed:10924499, PubMed:11815627, PubMed:19021774, PubMed:14504186).
Also removes the C-terminal residue from three other vasoactive peptides, neurotensin, kinetensin, and des-Arg bradykinin, but is not active on bradykinin (PubMed:10969042, PubMed:11815627).
Also cleaves other biological peptides, such as apelins (apelin-13, [Pyr1]apelin-13, apelin-17, apelin-36), casomorphins (beta-casomorphin-7, neocasomorphin) and dynorphin A with high efficiency (PubMed:11815627, PubMed:27217402, PubMed:28293165).
In addition, ACE2 C-terminus is homologous to collectrin and is responsible for the trafficking of the neutral amino acid transporter SL6A19 to the plasma membrane of gut epithelial cells via direct interaction, regulating its expression on the cell surface and its catalytic activity (PubMed:18424768, PubMed:19185582).
Isoform 2:
Non-functional as a carboxypeptidase.
1 Publication
(Microbial infection) Acts as a receptor for human coronaviruses SARS-CoV and SARS-CoV-2, as well as human coronavirus NL63/HCoV-NL63.
13 Publications
Isoform 2:
(Microbial infection) Non-functional as a receptor for human coronavirus SARS-CoV-2.
Regulated by chloride and fluoride, but not bromide (PubMed:11815627). Chloride increases angiotensin I and decreases angiotensin II cleavage (PubMed:19021774). Inhibited by MLN-4760, cFP_Leu, and EDTA (PubMed:15231706, PubMed:10924499), but not by the ACE inhibitors lisinopril, captopril and enalaprilat (PubMed:10969042, PubMed:10924499). Highly potent and selective in vitro ACE2 inhibitors were identified (PubMed:12358520).
１型膜タンパク質、ホモ２量体
N-glycosylation on Asn-90 may limit SARS infectivity.5 Publications
Proteolytic cleavage by ADAM17 generates a secreted form (PubMed:15983030, PubMed:33713620). Also cleaved by serine proteases: TMPRSS2, TMPRSS11D and HPN/TMPRSS1.6 Publications
Phosphorylated. Phosphorylation at Tyr-781 probably inhibits interaction with AP2M1 and enables interactions with proteins containing SH2 domains.
Angiotensin-converting enzyme
https://www.uniprot.org/uniprot/P12821
Converts angiotensin I to angiotensin II by release of the terminal His-Leu, this results in an increase of the vasoconstrictor activity of angiotensin. Also able to inactivate bradykinin, a potent vasodilator. Has also a glycosidase activity which releases GPI-anchored proteins from the membrane by cleaving the mannose linkage in the GPI moiety.
Miscellaneous
Inhibitors of ACE are commonly used to treat hypertension and some types of renal and cardiac dysfunction.
The glycosidase activity probably uses different active site residues than the metalloprotease activity.
Catalytic activity
Release of a C-terminal dipeptide, oligopeptide-|-Xaa-Yaa, when Xaa is not Pro, and Yaa is neither Asp nor Glu. Thus, conversion of angiotensin I to angiotensin II, with increase in vasoconstrictor activity, but no action on angiotensin II. EC:3.4.15.1
Activity regulation
Strongly activated by chloride. Specifically inhibited by lisinopril, captopril and enalaprilat.
Ubiquitously expressed, with highest levels in lung, kidney, heart, gastrointestinal system and prostate. Isoform Testis-specific is expressed in spermatocytes and adult testis.
Up-regulated in failing heart.
