Renin-Angiotensin System (RAS) is a critical regulator of blood pressure homeostasis. The protease renin cleaves angiotensinogen into inactive decameric peptide angiotensin-I (Ang-I). Angiotensin-converting enzyme (ACE) then cleaves C-terminal dipeptide from Ang-I to form an active octamer angiotensin-II (Ang-II), which can contribute to hypertension by promoting vascular smooth muscle vasocontriction and renal tubule sodium reabsorption. ACE can also cleave many other small peptides including the vasodialating peptide bradykinin into inactive fragment, cleave Alzheimer amyloid beta-peptide (Abeta), retard Abeta aggregation, deposition and fibril formation. ACE mutant mice display spontaneous hypotension, partial male infertility and kidney malformations. ACE is found in somatic (s-ACE) and testicular/germinal (t-ACE) isoforms. The products of renin and ACE catalysis, namely Ang1-10 and Ang1-8 can also be by another peptidase, ACE-2 to Ang1-9 and Ang1-7, respectively. ACE-2 and ACE (s-ACE and t-ACE) are made as transmembrane (TM) proteins but these enzymes also exist as soluble, truncated forms lacking the TM and cytosolic domains.

ACE or ACE1 (also known as dipeptidyl carboxypeptidase-1, DCP1; Kininase-II, ACE1) gene has been mapped at human chromosome 17q23. The s-ACE and t-ACE isoforms are generated by alternative splicing of ACE-2 gene. Somatic-ACE, a Zn (II) containing dipeptidyl carboxy peptidase is a single chain glycoprotein with a molecular mass of ~140kDa. The s-ACE enzymes from mouse (1312aa), rat (1313aa) and human (1306aa) contain two large areas of homologous sequence, each containing catalytic site and a Zn-binding region. These homologous regions are approximately half the size of whole s-ACE. The s-ACE is expressed in many somatic tissue tissues, including vascular endothelial cells, renal epithelial cells, and testicular Leydig cells. In contrast to s-ACE, the t-ACE enzymes (~80 kDa) from mouse (732aa), rat (775aa) and human (732aa) contain only one active site and are expressed only in sperms. The soluble ACE is present present in serum and seminal, amniotic and cerebrospinal fluids. The t-ACE is identical, from residue 37 to its C-terminus, to the second half or C-terminus of s-ACE. The t-ACE from mouse, rat and human are ~72% identical to each other in their aa seq.

ACE-2 (also known as ACE-2 and ACE homolog, ACEH) gene has been mapped at human chromosome Xp22. ACE-2 enzymes from human (805aa) and mouse (798aa) are single chain proteins with 40% seq homology to N- and C-terminal domains of ACE. However, in contrast to s-ACE which consists of two catalytic sites, ACE-2 contains only one active site. Unlike s-ACE and t-ACE which are dipeptidyl-carboxypeptidases, ACE-2 acts as a carboxypeptidase, cleaving single residue from Ang-I, generating Ang1-9 and a single residue from Ang-II to generate Ang1-7. ACE-2 can cleave angiotensin-I but not bradykinin and the enzyme activity is not inhibited by the ACE inhibitors. This enzyme is expressed highly in heart, kidney and testis and moderately in colon, small intestine and ovary. ACE-2 is an essential regulator of heart fuction because targeted disruption of this enzyme in mice results in severe cardiac contractility defect, increased angiotensin-II levels and upregulation of hypoxia-induced genes in the heart.

m=mouse; r=rat; h=human; b=bovine; d=dog; ~CT or ~NT=near C or N-terminus. EC=Extracellular; CP=Cytoplasmic domain;

* Expected antibody crossreactivity information is mostly based upon high (>70%) sequence conservation of antigenic/control peptides in various species. When antibody crossreactivity has actually been experimentally confirmed in various species, it will be mentioned in the appropriate data sheets.

"Neat Antisera or antisera" are the unpurified antiserum and it is suitable for ELISA and Western.
"Affinity pure" IgG may be more suitable for immunohistochemical (IHC) applications and to reduce background in most immunological applications including ELISA and Western.
"Control peptides" can not be used for Western as they are very short peptides. They are intended for ELISA or antibody blocking studies to establish antibody specificity.
Western blot +ve protein controls, where available, are semi-pure, pure or recombinant proteins that are formulated in SDS-PAGE sample buffer (reduced). They are recommended to be used for Western (load 10 ul/lane) for visulization with antibodies.