Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.15.1 (ACE)
 18,300 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The role of rat intestinal angiotensin-converting enzyme (ACE; E.C 3.4.15.1) in the digestion and absorption of dietary protein was investigated. Enzyme activity was associated with the brush-border membrane fraction, with the highest activity in the proximal to midregion of the small intestine. Preliminary enzyme characterization studies were carried out using purified brush-border membrane preparations. When a variety of N-blocked synthetic peptides were used as potential substrates for ACE, activity was highest with those containing proline at the carboxy terminal position. The hydrolytic rates observed with these prolyl peptides were comparable to those observed when major digestive peptidases of the brush-border membrane such as aminopeptidase N and dipeptidyl aminopeptidase IV were assayed. When isolated rat jejunum was perfused in vivo with solutions of Bz-Gly-Ala-Pro, the dipeptide Ala-Pro was the main hydrolytic product detected in the perfusates. Absorption rates of the constituent amino acids, alanine and proline, depended on the concentration of peptide perfused. Captopril, an active site specific ACE inhibitor, significantly inhibited hydrolysis and absorption of constituent amino acids from Bz-Gly-Ala-Pro. These results show that intestinal brush-border membrane ACE functions as a digestive peptidase in addition to its role as a regulator of biologically active peptides in other tissues.
 ...
PMID:Role of rat intestinal brush-border membrane angiotensin-converting enzyme in dietary protein digestion. 282 4

It is known that the serum level of glycylproline aminopeptidase (Gly-Pro-AP) is decreased in the patients with rheumatoid arthritis. In the present study, the serum levels of various hydrolytic enzymes were tested in such patients. In comparison to the controls, many enzymes, including Ala-AP, Ser-AP, Phe-AP, Gly-Pro-AP, Gly-Pro-Leu-AP, dipeptidyl carboxypeptidase (angiotensin converting enzyme), and esterase, showed significantly decreased activities in the patients' sera. Only the activity of Trp-AP was significantly increased. Of these enzymatic activities in serum, several ones including those of Gly-Pro-AP, Ala-AP, Phe-AP, trypsin-like enzyme, and esterase, were significantly correlated with the severity of the disease. Although a part of these findings are compatible with previous observations, they suggest rather more extensive disorders of peptide metabolism in this immunological disease.
 ...
PMID:Decreased serum levels of various hydrolytic enzymes in patients with rheumatoid arthritis. 608 27

Antisera raised against specific renal brush border peptidases have been used to characterize vascular surface membrane angiotensin I converting enzyme (ACE; EC 3.4.15.1), aminopeptidase M (AmM; EC 3.4.11.2), and dipeptidyl(amino)peptidase IV (DAP IV; EC 3.4.14.5) by techniques of differential solubilization, fused-rocket immunoelectrophoresis and crossed immunoelectrophoresis. The vascular membrane-bound enzymes are immunologically indistinguishable from their brush border counterparts and can be solubilized by treatment with detergent and/or papain. The electrophoretic mobilities of the papain-treated forms of each enzyme were greater than those of the detergent-treated forms. This increased mobility is associated with the removal of small, hydrophobic, non-antigenic components of the enzymes. Regardless of the method of solubilization, the electrophoretic mobilities of the vascular enzymes were greater than those of the brush border enzymes. However, after treatment with neuraminidase to remove sialic acid, their respective mobilities were similar. The mobilities of serum AmM and DAP IV were identical to the respective papain-solubilized vascular enzymes both before and after neuraminidase. Thus, like the brush border enzymes, the data presented are consistent with the model that vascular ACE, AmM and DAP IV are intrinsic membrane peptidases bound to their surface membranes by small, non-antigenic, hydrophobic anchors associated with the lipid bilayer. In addition, these vascular surface membrane peptidases are similar to and may be a source of the circulating enzymes.
 ...
PMID:Immunoelectrophoretic analysis of vascular, membrane-bound angiotensin I converting enzyme, aminopeptidase M, and dipeptidyl(amino)peptidase IV. 614 48

Dipeptidylpeptidase IV (EC 3.4.14.5), an enzyme which metabolizes substance P, is present in crude homogenates of hog mesenteric artery and aorta. Its subcellular localization is closely correlated with the plasma membrane marker enzyme 5'-nucleotidase (EC 3.1.3.5) in addition to the kinin and angiotensin metabolizing enzymes angiotensin I converting enzyme (EC 3.4.15.1) and aminopeptidase M (EC 3.4.11.2). The highest level of dipeptidylpeptidase IV is found on the surface membrane-enriched fraction and is immunologically identical to the kidney brush border-bound enzyme. Vascular dipeptidylpeptidase IV sequentially removes the N-terminal Arg1-Pro2 and Lys3-Pro4 dipeptides of substance P and exposes the biologically active C-terminal heptapeptide product to rapid degradation by vascular aminopeptidases.
 ...
PMID:Mesentery vascular metabolism of substance P. 618 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.
 ...
PMID:Metabolism of substance P and neurokinin A by human vascular endothelium and smooth muscle. 752 48

Alveolar macrophages protect the lungs against noxious agents. Proteases and peptidases are essential for this defense and many metabolic activities. Human alveolar macrophages were evaluated for the presence of six important peptidases. Deamidase, a serine peptidase identical with the lysosomal protective protein and possibly with cathepsin A, had high specific activity in alveolar macrophages and is also present in cultured mouse J774A.1 and human U937 cells, used for the sake of comparison. In fractionated J774A cells, most of the deamidase activity was in the lysosomal fraction and in the final supernatant. Deamidase in human alveolar macrophages, obtained by bronchoalveolar lavage from 23 patients, cleaved dansyl-Phe-Leu-Arg at a rate of 2.26 mumol/h/mg protein and hydrolyzed the chemotactic peptide N-f-Met-Leu-Phe even faster, at a rate of 53.1 mumol/h/mg protein, the highest activity for this enzyme with any of the cells we tested. Rabbit antiserum, elicited with the recombinant partial sequence of the enzyme, immunoprecipitated 77-88% of the macrophage deamidase. In immunocytochemistry, this antiserum localized deamidase within the human macrophages. The enzyme was inhibited by diisopropylfluorophosphate (DFP; 1 mM) and by ebelactone B (10 microM), noncompetitively. The mRNA of deamidase was detected in mouse macrophages by Northern blot; the two protein chains of deamidase were shown in human macrophages by Western blot. In addition, two other serine peptidases were also highly active in macrophages: dipeptidyl peptidase IV (1.38 mumol/h/mg protein) and prolylcarboxypeptidase (0.72 mumol/h/mg protein). The activity of plasma membrane zinc metallopeptidases, neutral endopeptidase 24.11 and carboxypeptidase M, in contrast, was low or absent (angiotensin I converting enzyme; kininase II).(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Plasma membrane-bound and lysosomal peptidases in human alveolar macrophages. 762 87

The cell-surface expression of endopeptidase-24.11 (EC 3.4.24.11) on Caco-2 cells cultured to confluency is markedly heterogeneous unlike that of dipeptidylpeptidase IV (EC 3.4.14.5). Here we have investigated the cell-surface expression of three other ectopeptidases: angiotensin converting enzyme (EC 3.4.15.1), aminopeptidase N (EC 3.4.11.2) and aminopeptidase W (EC 3.4.11.16). We show by indirect immunofluorescent staining that these three enzymes are present on the surface of some cells but not on others. However, these enzymes were detected in the majority of detergent-permeabilised Caco-2 cells indicating the presence of intracellular pools of these enzymes. This suggests that there may either be differential regulation of apical transport for these peptidases or that they recycle at different rates.
 ...
PMID:Mosaic expression of membrane peptidases by confluent cultures of Caco-2 cells. 809 58

The distribution profiles of brush border membrane activities of endopeptidase-24.11, angiotensin converting enzyme (ACE), and dipeptidyl peptidase IV (DPP IV) along the rabbit intestine were examined. DPP IV had the lowest activity in the duodenum and much higher in other segments. In those segments, its activities were similar. As regards endopeptidase-24.11 and ACE, the jejunum had the highest activities, followed by the duodenum and the ileum. Activities of these two enzymes were lower in the distal intestine. The decline of ACE activity toward the distal end was more dramatic than that of endopeptidase-24.11 activity. The results suggest that, along the intestine, endopeptidase-24.11 and ACE have similar distribution profiles while DPP IV has a different distribution pattern.
 ...
PMID:Distribution of brush-border membrane peptidases along the rabbit intestine: implication for oral delivery of peptide drugs. 809 14

The angiotensin I-converting enzyme (ACE) activity was studied in 2 experimental models of acute renal failure: (a) rats treated with a single injection of mercuric chloride (1.5 mg/kg) and (b) rats treated with a single injection of potassium dichromate (15 mg/kg). Rats were sacrificed 24 and 48 h after mercuric chloride or potassium dichromate injection. ACE activity was measured in urine, serum, and kidney. These data were compared with vehicle-treated rats. Rats with acute renal failure had proteinuria, polyuria, and decreased creatinine clearance. The damage to the kidney proximal tubule was evident by (a) the histological analysis at light and electron microscopy, (b) the augmentation in the urinary excretion of dipeptidyl aminopeptidase IV and N-acetyl-beta-D-glucosaminidase, and (c) the low molecular weight proteinuria pattern. In addition, the histological analysis at the ultrastructural level showed normal glomeruli appearance. The above data suggest that the increased urinary excretion of enzymes and proteins in rats with acute renal failure is a consequence of tubular injury. Urinary and serum ACE activities increased and kidney ACE activity decreased. Our data suggest that the increase in urine ACE activity may be due to the kidney proximal tubule damage. This work supports the contention that an increase in urine ACE may be an indicator of injury to the proximal tubule.
 ...
PMID:Urinary angiotensin I-converting enzyme activity is increased in experimental acute renal failure. 871 86

Neuropeptide Y is one of the most abundant neuropeptides in the central and peripheral nervous systems and its sequence is highly conserved among species. A number of key physiological roles for NPY are now emerging, especially in the control of feeding and energy homeostasis. Other physiological actions of NPY are also reviewed. The metabolism of NPY has been examined by employing certain purified ectopeptidases and by using different membrane preparations. These approaches reveal that NPY is processed at its N-terminus by two proline-preferring aminopeptidases: aminopeptidase P and dipeptidyl peptidase IV. The action of the latter enzyme generates NPY (3-36) which has previously been shown to be a selective agonist at the Y2 class of NPY receptor. Thus, post-secretory processing of NPY can modify receptor selectivity. NPY is found to be resistant to the action of two other membrane aminopeptidases (N and W), and to the action of angiotensin converting enzyme. However, it is a substrate for endopeptidase-24.11 (K(m) = 15.4 microM) which can cleave the Tyr20-Tyr21 and Leu30-Ile31 bonds consistent with the known specificity of the enzyme. In striatal synaptic and renal brush border membranes, NEP is shown to be the major NPY hydrolysing activity but plays a lesser role in intestinal brush border membranes. Knowledge of the proteolytic processing of NPY should aid in the design of stable analogues of this neuropeptide.
 ...
PMID:Metabolism and functions of neuropeptide Y. 889 76


<< Previous 1 2 3 4 5 Next >>