scholarly journals Shedding of somatic angiotensin-converting enzyme (ACE) is inefficient compared with testis ACE despite cleavage at identical stalk sites

2000 ◽  
Vol 347 (3) ◽  
pp. 711-718 ◽  
Author(s):  
Zenda L. WOODMAN ◽  
Sylvester Y. OPPONG ◽  
Sarah COOK ◽  
Nigel M. HOOPER ◽  
Sylva L. U. SCHWAGER ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Cleavage Site ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Analytical Techniques ◽  
Human Testis ◽  
Converting Enzyme ◽  
Substrate Preferences

The somatic and testis isoforms of angiotensin-converting enzyme (ACE) are both C-terminally anchored ectoproteins that are shed by an unidentified secretase. Although testis and somatic ACE both share the same stalk and membrane domains the latter was reported to be shed inefficiently compared with testis ACE, and this was ascribed to cleavage at an alternative site [Beldent, Michaud, Bonnefoy, Chauvet and Corvol (1995) J. Biol. Chem. 270, 28962-28969]. These differences constitute a useful model system of the regulation and substrate preferences of the ACE secretase, and hence we investigated this further. In transfected Chinese hamster ovary cells, human somatic ACE (hsACE) was indeed shed less efficiently than human testis ACE, and shedding of somatic ACE responded poorly to phorbol ester activation. However, using several analytical techniques, we found no evidence that the somatic ACE cleavage site differed from that characterized in testis ACE. First, anti-peptide antibodies raised to specific sequences on either side of the reported cleavage site (Arg1137/Leu1138) clearly recognized soluble porcine somatic ACE, indicating that cleavage was C-terminal to Arg1137. Second, a competitive ELISA gave superimposable curves for porcine plasma ACE, secretase-cleaved porcine somatic ACE (eACE), and trypsin-cleaved ACE, suggesting similar C-terminal sequences. Third, mass-spectral analyses of digests of released soluble hsACE or of eACE enabled precise assignments of the C-termini, in each case to Arg1203. These data indicated that soluble human and porcine somatic ACE, whether generated in vivo or in vitro, have C-termini consistent with cleavage at a single site, the Arg1203/Ser1204 bond, identical with the Arg627/Ser628 site in testis ACE. In conclusion, the inefficient release of somatic ACE is not due to cleavage at an alternative stalk site, but instead supports the hypothesis that the testis ACE ectodomain contains a motif that activates shedding, which is occluded by the additional domain found in somatic ACE.

scholarly journals Characterization of the first non-insect invertebrate functional angiotensin-converting enzyme (ACE): leech TtACE resembles the N-domain of mammalian ACE

2004 ◽  
Vol 382 (2) ◽  
pp. 565-573 ◽  
Author(s):  
Guillaume RIVIÈRE ◽  
Annie MICHAUD ◽  
Laurence DELOFFRE ◽  
Franck VANDENBULCKE ◽  
Angélique LEVOYE ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Active Site ◽  
Active Sites ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Inhibitory Effect ◽  
Converting Enzyme ◽  
Ovary Cells

Angiotensin-converting enzyme (ACE) is a zinc metallopeptidase that plays a major role in blood homoeostasis and reproduction in mammals. In vertebrates, both transmembrane and soluble ACE, containing one or two homologous active sites, have been characterized. So far, several ACEs from invertebrates have been cloned, but only in insects. They are soluble and display a single active site. Using biochemical procedures, an ACE-like activity was detected in our model, the leech, Theromyzon tessulatum. Annelida is the most distant phylum in which an ACE activity has been observed. To gain more insight into the leech enzyme, we have developed a PCR approach to characterize its mRNA. The approx. 2 kb cDNA has been predicted to encode a 616-amino-acid soluble enzyme containing a single active site, named TtACE (T. tessulatum ACE). Surprisingly, its primary sequence shows greater similarity to vertebrates than to invertebrates. Stable in vitro expression of TtACE in transfected Chinese-hamster ovary cells revealed that the leech enzyme is a functional metalloprotease. As in mammals, this 79 kDa glycosylated enzyme functions as a dipeptidyl carboxypeptidase capable of hydrolysing angiotensin I to angiotensin II. However, a weak chloride inhibitory effect and acetylated N-acetyl-SDKP (Ac SDAcKP) hydrolysis reveal that TtACE activity resembles that of the N-domain of mammalian ACE. In situ hybridization shows that its cellular distribution is restricted to epithelial midgut cells. Although the precise roles and endogenous substrates of TtACE remain to be identified, characterization of this ancestral peptidase will help to clarify its physiological roles in non-insect invertebrate species.

scholarly journals Evaluation of Fab and F(ab′)2 Fragments and Isotype Variants of a Recombinant Human Monoclonal Antibody against Shiga Toxin 2

2010 ◽  
Vol 78 (3) ◽  
pp. 1376-1382 ◽  
Author(s):  
Donna E. Akiyoshi ◽  
Abhineet S. Sheoran ◽  
Curtis M. Rich ◽  
L. Richard ◽  
Susan Chapman-Bonofiglio ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Shiga Toxin ◽  
Chinese Hamster Ovary Cells ◽  
Human Monoclonal Antibody ◽  
Chinese Hamster ◽  
The Body ◽  
Neutralization Activity ◽  
Shiga Toxin 2

ABSTRACT 5C12 HuMAb is a human monoclonal antibody against the A subunit of Shiga toxin 2 (Stx2). We have previously shown that 5C12 HuMAb effectively neutralizes the cytotoxic effects of this toxin by redirecting its transport within the cell and also by neutralizing the toxin's ability to inhibit protein synthesis. The 5C12 HuMAb and its recombinant IgG1 version protect mice at a dose of 0.6 μg against a lethal challenge of Stx2. The contribution of the Fc region to this observed neutralization activity of the 5C12 antibody against Stx2 was investigated in this study. Using recombinant DNA technology, 5C12 isotype variants (IgG1, IgG2, IgG3, and IgG4) and antibody fragments [Fab, F(ab′)2] were expressed in Chinese hamster ovary cells and evaluated in vitro and in vivo. All four 5C12 isotype variants showed protection in vitro, with the IgG3 and IgG4 variants showing the highest protection in vivo. The Fab and F(ab′)2 fragments also showed protection in vitro but no protection in the mouse toxicity model. Similar results were obtained for a second HuMAb (5H8) against the B subunit of Stx2. The data suggest the importance of the Fc region for neutralization activity, but it is not clear if this is related to the stability of the full-length antibody or if the Fc region is required for effective elimination of the toxin from the body.

Interaction of mAb to angiotensin-converting enzyme (ACE) with antigen in vitro and in vivo: antibody targeting to the lung induces ACE antigenic modulation

1994 ◽  
Vol 6 (8) ◽  
pp. 1153-1160 ◽  
Author(s):  
Sergei Danilov ◽  
Elena Atochina ◽  
Holger Hiemisch ◽  
Tatiana Churak-ova ◽  
Aygul Moldobayeva ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Converting Enzyme ◽  
Antigenic Modulation ◽  
Antibody Targeting

DOCKING STUDY OF NOVEL N-SUBSTITUTED 2,5-BIS[(7-CHLOROQUINOLIN-4-YL)AMINO]PENTANOIC DERIVATIVES AS SELECTIVE HIGH-BINDER WITH ANGIOTENSIN CONVERTING ENZYME 2

INDIAN DRUGS ◽  
2020 ◽  
Vol 57 (08) ◽  
pp. 16-24
Author(s):  
Mohammed Oday Ezzat ◽  
Basma M. Abd Razik ◽  
Kutayba F. Dawood
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Active Site ◽  
Docking Study ◽  
World Health ◽  
Converting Enzyme ◽  
Angiotensin Converting Enzyme 2 ◽  
Pharmaceutical Properties ◽  
Novel Coronavirus

The prevalence of a novel coronavirus (2019-nCoV) in the last few months represents a serious threat as a world health emergency concern. Angiotensin-converting enzyme 2 (ACE2) is the host cellular receptor for the respiratory syndrome of coronavirus epidemic in 2019 (2019-nCoV). In this work, the active site of ACE2 is successfully located by Sitmap prediction tool and validated by different marketed drugs. To design and discover new medical countermeasure drugs, we evaluate a total of 184 molecules of 7-chloro-N-methylquinolin-4-amine derivatives for binding affinity inside the crystal structure of ACE2 located active site. A novel series of N-substituted 2,5-bis[(7-chloroquinolin-4-yl)amino]pentanoic acid derivatives is generated and evaluated for a prospect as a lead compound for (2019-nCoV) medication with a docking score range of (-10.60 to -8.99) kcal/mol for the highest twenty derivatives. Moreover, the ADME pharmaceutical properties were evaluated for further proposed experimental evaluation in vitro or in vivo

Angiotensin-converting enzyme determination in plasma during therapy with converting enzyme inhibitor: two methods compared

1991 ◽  
Vol 37 (8) ◽  
pp. 1390-1393 ◽  
Author(s):  
T P Gorski ◽  
D J Campbell
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Spectrophotometric Method ◽  
Enzyme Inhibitor ◽  
Ang Ii ◽  
Converting Enzyme ◽  
Fluorometric Method ◽  
Converting Enzyme Inhibitor ◽  
Ace Activity

Abstract For normal and above-normal concentrations of angiotensin-converting enzyme (ACE; EC 3.4.15.1) activity in plasma, results of a manual fluorometric method [with hippuryl-histidyl-leucine (HHL), 5 mmol/L, as substrate] correlated well with those of an automated spectrophotometric method [with 3-(2-furylacryloyl)-L-phenylalanyl-glycyl-glycine (FAPGG), 2 mmol/L, as substrate]. However, for patients receiving converting enzyme inhibitor (CEI) therapy, the spectrophotometric method showed much greater suppression of plasma ACE activity than did the fluorometric method. To determine which of the two methods provided a more reliable indication of ACE inhibition in vivo, we measured plasma ACE, angiotensin I (ANG I), and angiotensin II (ANG II) in patients receiving the CEI perindopril. During perindopril therapy, changes in the ratio of ANG II:ANG I, an index of ACE activity in vivo, showed a close agreement with changes in plasma ACE activity measured with FAPGG as substrate, but not with HHL as substrate. We conclude that measurement of ACE activity in vitro with FAPGG as substrate provides a reliable measure of changes in conversion of ANG I to ANG II in vivo during CEI therapy.

Evaluation of the Toxicity of Intravenous Delivery of Auroshell Particles (Gold–Silica Nanoshells)

2012 ◽  
Vol 31 (6) ◽  
pp. 584-594 ◽  
Author(s):  
Shayne C. Gad ◽  
Kelly L. Sharp ◽  
Charles Montgomery ◽  
J. Donald Payne ◽  
Glenn P. Goodrich
Keyword(s):  
Water Solution ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Gold Nanoshells ◽  
Sprague Dawley ◽  
Ovary Cells ◽  
Good Laboratory ◽  
Chromosomal Aberration Assay

Gold nanoshells (155 nm in diameter with a coating of polyethylene glycol 5000) were evaluated for preclinical biocompatibility, toxicity, and biodistribution as part of a program to develop an injectable device for use in the photothermal ablation of tumors. The evaluation started with a complete good laboratory practice (GLP) compliant International Organization for Standardization (ISO)-10993 biocompatibility program, including cytotoxicity, pyrogenicity (US Pharmacopeia [USP] method in the rabbit), genotoxicity (bacterial mutagenicity, chromosomal aberration assay in Chinese hamster ovary cells, and in vivo mouse micronucleus), in vitro hemolysis, intracutaneous reactivity in the rabbit, sensitization (in the guinea pig maximization assay), and USP/ISO acute systemic toxicity in the mouse. There was no indication of toxicity in any of the studies. Subsequently, nanoshells were evaluated in vivo by intravenous (iv) infusion using a trehalose/water solution in a series of studies in mice, Sprague-Dawley rats, and Beagle dogs to assess toxicity for time durations of up to 404 days. Over the course of 14 GLP studies, the gold nanoshells were well tolerated and, when injected iv, no toxicities or bioincompatibilities were identified.

scholarly journals An Engineered Complement Factor H Construct for Treatment of C3 Glomerulopathy

2018 ◽  
Vol 29 (6) ◽  
pp. 1649-1661 ◽  
Author(s):  
Yi Yang ◽  
Harriet Denton ◽  
Owen R. Davies ◽  
Kate Smith-Jackson ◽  
Heather Kerr ◽  
...  
Keyword(s):  
Chinese Hamster Ovary Cells ◽  
Alternative Pathway ◽  
Treatment Options ◽  
Chinese Hamster ◽  
Factor H ◽  
Complement Factor H ◽  
Complement Factor ◽  
C3 Glomerulopathy

Background C3 glomerulopathy (C3G) is associated with dysregulation of the alternative pathway of complement activation, and treatment options for C3G remain limited. Complement factor H (FH) is a potent regulator of the alternative pathway and might offer a solution, but the mass and complexity of FH makes generation of full-length FH far from trivial. We previously generated a mini-FH construct, with FH short consensus repeats 1–5 linked to repeats 18–20 (FH1–5^18–20), that was effective in experimental C3G. However, the serum t1/2 of FH1–5^18–20 was significantly shorter than that of serum-purified FH.Methods We introduced the oligomerization domain of human FH-related protein 1 (denoted by R1–2) at the carboxy or amino terminus of human FH1–5^18–20 to generate two homodimeric mini-FH constructs (FHR1–2^1–5^18–20 and FH1–5^18–20^R1–2, respectively) in Chinese hamster ovary cells and tested these constructs using binding, fluid-phase, and erythrocyte lysis assays, followed by experiments in FH-deficient Cfh−/− mice.Results FHR1–2^1–5^18–20 and FH1–5^18–20^R1–2 homodimerized in solution and displayed avid binding profiles on clustered C3b surfaces, particularly FHR1–2^1–5^18–20. Each construct was >10-fold more effective than FH at inhibiting cell surface complement activity in vitro and restricted glomerular basement membrane C3 deposition in vivo significantly better than FH or FH1–5^18–20. FH1–5^18–20^R1–2 had a C3 breakdown fragment binding profile similar to that of FH, a >5-fold increase in serum t1/2 compared with that of FH1–5^18–20, and significantly better retention in the kidney than FH or FH1–5^18–20.Conclusions FH1–5^18–20^R1–2 may have utility as a treatment option for C3G or other complement-mediated diseases.

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