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)

Antiontensin-converting enzyme (peptidyldipeptide hydrolase, EC 3.4.15.1) has been solubilized from canine pulmonary particles and purified to apparent homogeneity. A value of approx. 140000 was estimated for the molecular weight of the native and the reduced, denatured forms of the enzyme. No free NH2-terminal residue was detected by the dansylation procedure. Carbohydrate accounted for 17% of the weight of the enzyme, and the major residues were galactose, mannose and N-acetylglucosamine with smaller amounts of sialic acid and fucose. Removal of sialic acid residues with neuraminidase did not alter enzymatic activity. The enzyme contained one molar equivalent of zinc. Addition of this metal reversed stimulation and inhibition of activity observed in the presence of Co2+ and Mn2+, respectively. Immunologic homology of pure dog and rabbit enzymes was demonstrable with goat antisera. Fab fragments and intact IgG antibodies displayed similar inhibition dose vs. response curves with homologous enzyme, whereas the fragments were poor inhibitors of heterologous activity compared to the holoantibodies. The canine glycoprotein was much less active than the rabbit preparation in catalyzing hydrolysis of Hip-His-Leu. In contrast, the two enzymes exhibited comparable kinetic parameters with angiotensin I as substrate.
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PMID:Canine pulmonary angiotensin-converting enzyme. Physicochemical, catalytic and immunological properties. 20 22

Analysis of carcinoembryonic antigen (CE)-reactive glycoproteins from liver metastasis of primary colon and breast tumors and from primary breast tumors has been carried out by affinity chromatography on concanavalin A (Con A)-Sepharose. Three CEA-reactive glycoproteins from colon tumors (liver metastasis) with different binding capacity to Con A have been separated and further purified by gel filtration. Of the 3 CEA-reactive glycoproteins, 1 of them did not bind to Con A. Both Con A-binding and nonbinding CEA-reactive glycoproteins were immunologically indistinguishable when tested with a reference goat anti-CEA (ACE, 67-70; Dr. C.W. Todd and Dr. M.L. Egan), as well as with a variety of rabbit anti-CEA and anti-CEA (nonbinding) prepared in this laboratory. Carbohydrate analysis showed that mannose content of different purified CEA preparations or nonbinding CEA did not differ appreciably. N-Acetylglucosamine content of purified CEA preparations, however, varied considerably, suggesting that this sugar may impart the specificity of binding of CEA to Con A. The purified CEA preparations differed in their ability to inhibit the binding of 125l-labeled CEA to goat anti-CEA. One of the purified CEA preparations had 3- to 8-fold greater inhibitory capacity when compared to other preparations and shared a partial identity with a glycoprotein present in the extracts of fetal colon. The glycoprotein extracts of primary breast tumors did not contain a CEA that was immunologically identical to CEA present in colon tumors, whereas the liver metastasis of primary breast tumors showed several CEA-reactive glycoproteins as judged by radioimmunoassay. However, these CEA-reactive glycoproteins did not have any antigenic relationship with CEA from colon tumors when tested by double diffusion and immunoelectrophoresis. In conclusion, when Con A affinity chromatography of tumor glycoproteins is carried out under defined conditions and with the use of appropriate antisera, it is possible to delineate the presence or absence of CEA in tumors of nonentodermal origin.
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PMID:Immunochemical studies on carcinoembryonic antigen-reactive glycoproteins from carcinomas of the colon and breast separated by concanavalin A affinity chromatography. 97 8

The bindings of perindopril and of its active metabolite perindoprilat to human serum, isolated proteins and to erythrocytes were studied by equilibrium dialysis. Within the therapeutic concentrations range, perindopril was 74% bound to serum involving a non-saturable process, NKa = 2.87. The main binders are serum albumin and alpha 1-acid glycoprotein. The serum binding of perindoprilat involved two successive steps. First, a saturable high-affinity binding (Ka: 2.8 x 10(9) M-1) occurred, involving probably the angiotensin converting enzyme (ACE). The second binding step was non-saturable with a very weak binding capacity, NKa = 0.15, quite superimposable to the HSA bound perindoprilat. Free fatty acids (FFA) did not alter the binding to HSA. The binding of both compounds to erythrocytes was low especially with perindopril, when measured in the presence of plasma. A significant correlation showed that the overall serum binding percentage of both drugs was essentially determined by HSA concentration. Serum binding was decreased in renal failure or cirrhosis, this result was principally linked to the hypoalbuminemia. Interactions with other drugs were limited to the binding of salicylate, tolbutamide and digitoxin to HSA.
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PMID:Specific and high affinity binding of perindoprilat, but not of perindopril to blood ACE. 133 Sep 41

Increasing evidence implicates endothelial cell dysfunction in the development of diabetic microvascular disease, but its precise nature is elusive. This study sought to extend previous observations on the association between diabetes and the endothelial cell-derived glycoprotein von Willebrand factor (vWF), in a study of 777 diabetic patients. Compared with a mean of 1.07 +/- 0.18 iu/ml in a non-diabetic population, vWF was found to be elevated to 1.59 +/- 0.14 iu/ml in the whole sample, but particularly in those with retinopathy or microalbuminuria. It was studied whether such an elevation is part of an acute phase response, or is accompanied by other indicators of endothelial cell dysfunction. Plasma samples were examined for vWF, and serum for angiotensin converting enzyme (ACE), C-Reactive protein (CRP), IgG and IgM endothelial cell-binding antibodies (anti-EC Ig). A strong positive association was found (p less than 0.005) between the extent of elevation of vWF and the presence of diabetic retinopathy. ACE and CRP were rarely raised, and their levels did not correlate with either diabetic retinopathy or vWF levels. However, 52% of the patients had circulating anti-EC IgG or IgM, although their presence did not correlate with retinopathy, or with vWF, ACE or CRP. Thus diabetic retinopathy and probably nephropathy is associated with a specific but generalised disturbance of vascular endothelial cell function.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Diabetes is associated with a high incidence of endothelial-binding antibodies which do not correlate with retinopathy, von Willebrand factor, angiotensin-converting enzyme or C-reactive protein. 166 55

Neurotensin (NT) endopeptidase (EC 3.4.24.16) has been purified about 800-fold from pig brain by four sequential chromatographic steps depending on ion-exchange and hydrophobic interactions. Two types of preparation were studied: one from a Triton X-100-solubilized membrane fraction, and the other from the soluble fraction containing 90% or more of the total activity in the homogenate. NT endopeptidase activity was monitored by high-precision liquid chromatography of the two peptide products, characterized as NT-(1-10) and NT-(1-8), resulting from cleavage of the Pro10-Tyr11 and Arg8-Arg9 bonds respectively. As purification proceeded, from both membranes and cytosol, the yield of the two products achieved a constant ratio of 5:1 and this ratio was reproduced in repeated purifications. However, a distinct peptidase which hydrolysed exclusively at the Arg8-Arg9 bond was partially resolved from NT endopeptidase by chromatography on hydroxyapatite, and this activity was further purified and assigned to endopeptidase-24.15 (EC 3.4.24.15). SDS/PAGE of both preparations of neurotensin endopeptidase revealed a major band of apparent Mr 75000, and treatment of the membrane-associated form with N-Glycanase gave no evidence that the enzyme was a glycoprotein. The membrane-associated and cytosol forms of NT endopeptidase activities, monitored for both NT-(1-10) and NT-(1-8) products, were compared in their responses to 1,10-phenanthroline, EDTA, dithiothreitol (DTT) and some synthetic site-directed inhibitors of endopeptidase-24.15 or peptidyl dipeptidase A. The effects revealed no significant differences between the two preparations, nor did the reagents discriminate between the activities generating the two NT fragments. The partially purified form of endopeptidase-24.15 was also included in this comparison: while some responses were similar, this peptidase was distinguishable in its activation by DTT and its relative resistance to inhibition by EDTA. Both forms of NT endopeptidase were found to hydrolyse other substrates, including Boc-Phe-Ala-Ala-Phe-4-aminobenzoate, bradykinin and substance P (these at faster rates than neurotensin), as well as dynorphin A-(1-8) and luliberin. The bonds hydrolysed in these neuropeptides, as well as in angiotensins I and II and alpha-neoendorphin, were defined. These studies confirm that NT endopeptidase is distinct from endopeptidase-24.15. They further show that the former is a soluble enzyme, not an integral membrane protein, that it is not peptide-specific and that it might be more appropriately named. enzyme, not an integral membrane protein, that it is not peptide-specific and
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PMID:Purification and properties of a neurotensin-degrading endopeptidase from pig brain. 190 21

The peptides bradykinin and kallidin are released in response to noxious stimuli and mediate various physiological effects, including a direct stimulation of nociceptive afferent neurones. The nature of the receptor molecules through which these ligands act is presently unknown. We synthesised an iodinatable photoaffinity probe, N epsilon-4-azidosalicylylkallidin, and used it in an attempt to identify candidate bradykinin receptors on the NG108-15 neuroblastoma X glioma hybrid cell line. The ligand bound in subdued light to a particulate fraction of NG108-15 tumours and could be displaced by bradykinin with an IC50 of 0.33 nM. In a physiological assay, it behaved as an agonist equipotent with bradykinin. Gel analysis of the labelled products after photolysis of the iodinated ligand in the presence of NG108-15 cells or tumour membranes revealed bradykinin-blockable labelling of a glycoprotein with an Mr of 166,000. The probe was also able to label purified commercial angiotensin converting enzyme. The band labelled in NG108-15 cells was immunoprecipitable with a polyclonal antiserum to angiotensin converting enzyme, an enzyme shown to be present in low amounts in these preparations by direct binding using the iodinatable specific ligand MK351A.
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PMID:Construction of a physiologically active photoaffinity probe based on the structure of bradykinin: labelling of angiotensin converting enzyme but not candidate bradykinin receptors on NG108-15 cells. 254 Feb 73

Laminin, a high molecular weight glycoprotein, is one of the three principal constituents of basement membranes. It plays an important role in the interaction of cells with the basement membrane as it is involved in cell differentiation and proliferation. It may also be used in the metastatic diffusion process of the tumor. Serum concentration of laminin was measured by radioimmunoassay in 157 patients suffering from various malignancies. Laminin levels were significantly elevated in patients with metastatic breast carcinoma, and in patients with ovarian, stomach and colorectal cancers when compared with healthy controls. Good correlation could be found between serum laminin concentration and concentrations of other markers. The serum laminin level seems to be a valuable parameter for observation of the course of digestive malignancies, in association with the serum concentration of ACE, CA 19-9 and CA 50.
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PMID:[Assay of the laminin P1 using a radioimmunologic technic: applications in oncology]. 262 Jan 28

The value of BAL in three groups of diseases (sarcoidosis, lung fibrosis, inflammatory diseases of the bronchi) compared with a control group is described. The cellular components and total protein and glycoprotein as well as electrolyts and angiotension-converting enzyme were examined. In patients with sarcoidosis a higher retention of sodium ions was stated. ACE in BAL was without any hint to the activity of the disease. But for glycoproteins a higher permeability was proved. In several fractions of the BAL fluid were differences according to all examined parameters.
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PMID:[Cell and fluid permeability of the alveolar wall in sarcoidosis]. 283 38

In this article is given a survey on physiology and pharmacology of the opioid system. Opioid peptides are naturally occurring morphine-like acting metabolites of glycoprotein precursors. Of the opioid peptides proved hitherto in the organism met-, leu-enkephalin, dynorphin and beta-endorphin are characterized more in detail. Opioids react directly with opioid receptors. The opioid receptors are not a homogeneous system. Their distribution is depending on organs and species. Opioid peptides and receptors were proved within as well as outside the central nervous system. The main quantity of the endogenous beta-endorphin is stored in the pituitary gland. High concentrations of met-, leu-enkephalin and dynorphin are present in the gastrointestinal tract and in the adrenal glands. Opioid peptides are inactivated by enzymatic hydrolysis, in which case the splitting of the N-terminal tyrosine is decisive. The inactivation may be performed by amino peptidases, peptidyl dipeptide hydrolases or the angiotensin converting enzyme. The effect of the opioid peptides can be inhibited by opioid antagonists (naloxone, naloxazone). Up to now there are contradictory findings as to the presence of an endogenous opioid antagonist. In general, the presence of different opioid peptides and their different receptor preference indicate multiple functions in the organism. However, their physiological function is up to now only little clarified.
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PMID:[Stress and the endogenous opioid system. I. Physiology and pharmacology of opioid peptides]. 298 51

A high activity of renin was demonstrated in human pheochromocytoma tissue. This activity was inhibited by specific antibody raised against human renal renin, indicating that it was not due to the nonspecific actions of proteases such as cathepsin D. The specific renin shared some biochemical features with well-known kidney renin, such as molecular weight (47,000 daltons), optimum pH (6.0), the presence of trypsin-activatable inactive renin, and glycoprotein nature. However, the isoelectrofocusing pattern of renin from the pheochromocytoma differed from that of kidney and plasma renins hitherto reported, a discrepancy which could be interpreted as evidence for endogenous synthesis of the enzyme. Furthermore, angiotensin converting enzyme activity was found in the tissue. Since pheochromocytoma is considered to be of neural crest origin, these results provide biochemical and immunological evidence for the presence of the renin-angiotensin cycle within human neuronal cells.
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PMID:Biochemical identification of renin in human pheochromocytoma. 300 87


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