Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.15.1 (ACE)
18,300 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Biochemical responses of endothelial cells in culture to pharmacological or physiological stimuli are often extrapolated to define the behavior of the vascular endothelium in vivo. However, culture conditions cannot recreate the environment of endothelial cells in vivo. To compare cell functions in vivo and in vitro, we iodinated endothelial membrane proteins of both the perfused rabbit lung and cultured rabbit lung endothelial cells. Endothelial cell protein 125I-labeling in the perfused intact lung was catalyzed by lactoperoxidase and glucose oxidase immobilized on 3-10 microns polyacrylamide beads (Enzymobeads, Bio-Rad). Changes in 5-hydroxytryptamine uptake, angiotensin converting enzyme activity and perfusion pressure made before, during and/or after iodination were small, suggesting that the procedure does not grossly injury the lung. As confirmed by tissue autoradiography, iodination was confined to the vascular space. A subcellular "membrane" fraction of the whole homogenate was enriched for several iodinated proteins. Lectin binding further purified a library of putative iodinated endothelial membranes proteins, one of which was angiotensin-converting enzyme as shown by immunoprecipitation with goat anti-rabbit antibody to angiotensin-converting enzyme. Iodinated proteins of similar molecular weights were also isolated from cultured rabbit lung endothelium iodinated under the same conditions, thus confirming the endothelial lineage of proteins iodinated in the intact lung. We conclude that this technique labels endothelial surface proteins in the intact lung without causing observable tissue injury and thus should be valuable in the study of the physiology and pathophysiology of the vascular lining in vivo.
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PMID:In situ iodination of angiotensin-converting enzyme and other pulmonary endothelial membrane proteins. 253 64

Proper classification of patients into diffuse cutaneous and limited cutaneous subsets and the anticipation of complications are the keys to the management of individuals with systemic sclerosis (scleroderma). Patients with early diffuse disease and rapidly progressive skin thickening are at highest risk to develop serious internal organ involvement (intestine, lung, heart, kidney) and should be considered for disease modifying therapy. The targets of the disease and sites of possible intervention are vascular endothelium (vasoprotection agents), mononuclear cell subsets (immunosuppressive agents), and fibroblasts (colchicine, D-penicillamine). A number of new therapeutic agents with sound scientific rationale are undergoing therapy trials. Much can be done to improve the lifestyle of the scleroderma sufferer. The most dramatic recent development is the ability to reverse kidney involvement with prompt use of angiotensin converting enzyme inhibitors and modern methods of renal dialysis and transplantation. Scleroderma is not a hopeless disease.
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PMID:Treatment of systemic sclerosis. 267 35

Recent investigations suggest angiotensin converting enzyme (ACE) activity is generally decreased in normotensive pregnancy, but less is known about the level of activity of this enzyme in hypertensive pregnant subjects. The primary source of ACE is vascular endothelium and it can be measured in serum or plasma. In a preliminary investigation, we measured and compared diastolic blood pressure and serum ACE activity in 14 uncomplicated pregnant subjects during the third trimester, and in 16 subjects of similar gestation duration hospitalized with pregnancy-induced hypertension PIH. No patient had a positive history for, or evidence of, pulmonary or other metabolic disease. Compared with levels in normal pregnancy, serum ACE activity was found to be significantly elevated in PIH. In this study, this increase was not due to differences between the groups in maternal chronologic age or gestational duration. Further studies are necessary to determine if the increase in ACE activity precedes or follows development of clinically apparent PIH. If the former is the case, ACE activity might be a useful indicator of risk for PIH.
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PMID:Angiotensin converting enzyme activity in hypertensive pregnancy. 282 97

The cellular relationships between angiotensin converting enzyme (ACE) (EC 3.4.14.1) and angiotensin-like immunoreactivity (AGLI) were examined in the subfornical organ (SFO). Brains from adult rats were fixed by vascular perfusion with 3.75% acrolein and 2% paraformaldehyde. The region containing the SFO was then sectioned on a vibrating microtome. Partially permeabilized sections were immunocytochemically labeled using the peroxidase-antiperoxidase (PAP) or combined PAP and immunogold methods. Goat antiserum to ACE was localized to both non-neuronal and neuronal cells within the SFO. Intense peroxidase immunoreactivity for ACE was associated with the ventricular and basal surface of ependymal cells, the luminal surface of the vascular endothelium, portions of glial membranes exposed to extracellular spaces, and membranous organelles within neuronal processes. Two antisera raised in rabbits against angiotensin II showed peroxidase immunoreactivity within the extracellular spaces and throughout the cytoplasm of numerous axon terminals and a few perikarya and dendrites in the SFO. Axon terminals and dendrites also showed aggregates of AGLI in smooth membranes and vesicles near the plasmalemma. Gold labeling for AGLI was evident in only 6% of the axon terminals and in a smaller number of dendrites containing peroxidase immunoreactivity for ACE. The low incidence of terminals containing both markers appeared to at least partially reflect limited penetration of the 10 nm gold particles. These results provide the first ultrastructural evidence that ACE is associated with the plasmalemma and membranous organelles strategically located for interaction with precursors of angiotensin II or other peptides within the cerebrospinal fluid, extracellular spaces and neurons of the SFO.
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PMID:Dual peroxidase and colloidal gold-labeling study of angiotensin converting enzyme and angiotensin-like immunoreactivity in the rat subfornical organ. 301 92

Angiotensin-converting enzyme, although most prominent in vascular endothelium, has been identified in numerous tissues. Recent studies have indicated that several hormones, including glucocorticoids and thyroid hormone, may affect the activity of this enzyme. In the present study, angiotensin-converting enzyme was examined in homogenates of cultured human skin fibroblasts. Angiotensin-converting enzyme activity was measured by a radiometric assay using [Glycine-1-14C] Hippuryl-L-histidyl-L-leucine (1.1 mmol/L) as substrate, and was expressed as nmol hippuric acid formed per minute/mg protein. Angiotensin-converting enzyme was identified in all five cell strains tested, and the activity observed was 0.97 +/- 0.18 nmol/min/mg protein (mean +/- SE). The optimum pH was between 6.9 and 7.6, and optimum temperature was 37 degrees C, with loss of activity of 55 degrees C and higher. Buffer strength was optimized at Tris 0.025 mol/L, and 1.0 mol/L NaCl. Activity increased linearly with protein concentration and with time, and the Km = 1.14 mmol/L. The most potent inhibitor of fibroblast ACE was captopril (SQ 14,225) with an IC50 = 10(-10) mol/L; other inhibitors included SQ 20,881, EDTA, and phenanthroline. Competitive substrates included angiotensin-I, substance P, and bradykinin. Four hormones, T3 (10(-9)-10(-7) mol/L), 1,25 (OH)2D3 (10(-8)-10(-7) mol/L), dexamethasone (10(-7)-10(-6) mol/L), and a synthetic androgen, R1881 (10(-8)-10(-7) mol/L) were incubated with cells for 72 hours. In all incubations, there was no significant effect on cellular ACE activity induced by any agent. Angiotensin-converting enzyme activity in serum free media was less than 1% of cell activity and was unaltered by hormone treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Angiotensin-converting enzyme: characteristics in human skin fibroblasts. 302 Mar 42

Angiotensin-converting enzyme (ACE) is secreted by the vascular endothelium and serum activity may reflect endothelial damage. A study of 48 insulin-dependent diabetics, 15 with and 33 without evidence of diabetic retinopathy and 41 non-diabetic controls was performed. ACE activity was significantly elevated in the diabetics compared with controls (mean +/- SD 46 +/- 14 vs 35 +/- 9 U/l, p less than 0.001) (units in micromoles substrate converted/min/l serum). This elevation was more marked in diabetics with such evidence of microangiopathy as retinopathy or raised albumin excretion rate (AER) (51 +/- 14 U/l, p less than 0.0001), and also in those with raised AER alone (47.2 +/- 15 U/l, p less than 0.002). Patients with both raised AER and retinopathy had significantly higher ACE activities than those with no complications (53 +/- 15 vs 41.2 +/- 15 U/l, p less than 0.05). No correlation was found with glycosylated haemoglobin or smoking habits. We conclude that mean serum angiotensin converting enzyme activity is increased in insulin-dependent diabetes, particularly in those with evidence of microangiopathy and this may reflect microvascular damage.
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PMID:Angiotensin-converting enzyme (ACE): relationship to insulin-dependent diabetes and microangiopathy. 303 Jun 21

Angiotensin converting enzyme (ACE, EC 3.4.15.1) was purified to homogeneity from human kidney and its specific antibody was raised in the rabbit. The antibody cross-reacted equally with human enzymes from kidney, lung, intestine, plasma and urine. Immunofluorescent and immunoelectron microscopic observation indicated that the enzyme was located on the plasma membrane and micropinocytic vesicles at the luminal site of vascular endothelium in the lung. It was also present on the brush border, intercellular and basal infolding membranes of proximal tubular epithelium, but was not detected on the distal tubular epithelium or vascular endothelium in the kidney. ACE was demonstrated immunocytologically in human alveolar macrophages and renal carcinoma tissues. The carcinoma tissue contained a possible isoenzyme of ACE differing in part immunologically from the enzyme of normal kidney.
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PMID:Biochemistry of human converting enzyme. 303 82

Among the metabolic functions of the lungs are the formation, release, activation and inactivation of biologically active peptides. The following peptides may be present or formed in normal lung: vasoactive intestinal peptide or a peptide closely related to it, a spasmogenic peptide not yet fully identified, bradykinin, substance P, a bombesin-like peptide (especially in fetal and neonatal lung), and eosinophil-chemotactic peptides. These peptides are found in special neuroendocrine cells, in neurons, or in mast cells. Normal lung also inactivates bradykinin and activates angiotensin; both processes are catalysed by the same enzyme (kininase II or angiotensin-converting enzyme), located in pulmonary vascular endothelium. Pulmonary tumours and certain non-tumorous lesions can produce and release a variety of peptide hormones that are not normally generated by the lung in substantial amounts. This 'ectopic' secretion of hormones may be detectable only by sensitive assays or may result in specific clinical syndromes.
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PMID:The lung in relation to vasoactive polypeptides. 616 26

Twenty-four patients with sarcoidosis had normal serum angiotensin converting enzyme (SACE) values at time of diagnosis. Sixteen patients were in stage I and eight of these underwent complete remission and four followed a stable course. Seven of eight patients in stages II and III experienced improvement while receiving glucocorticoid treatment. In six, serial SACE measurements fell significantly, paralleling the clinical improvement. The data suggest that a normal SACE in stage I indicates a good prognosis. Patients in stages II and III with normal SACE levels may still have active disease potentially responsive to glucocorticoid treatment. The reduction of SACE while receiving treatment may be viewed as the "suppressible" SACE compartment, representing that portion of the enzyme elaborated by the granuloma or its cellular precursors. The level remaining after suppression by glucocorticoids may be considered "basal" SACE, probably related to normal turnover of SACE producing cells in vascular endothelium.
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PMID:Normal serum angiotensin converting enzyme activity in patients with newly diagnosed sarcoidosis. 631 94

Analysis of SP and NKA metabolism by human vascular endothelium, relative to that in human plasma, identified integrative, multiple pathways for the processing of circulating SP (but not NKA) by angiotensin-converting enzyme (ACE; EC 3.4.15.1), dipeptidyl(amino)peptidase IV (DAP IV; EC 3.4.14.5), and aminopeptidase M (AmM; EC 3.4.11.2). In contrast, SP and NKA, which may diffuse into or be neurally released within the vessel wall, were both metabolized by smooth muscle neutral endopeptidase-24.11 (NEP-24.11; EC 3.4.24.11). Collectively, these studies indicate peptide-specific and site-specific differential processing of SP and NKA by human plasma and vasculature.
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PMID:Metabolism of substance P and neurokinin A by human vascular endothelium and smooth muscle. 752 48


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