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)

Angiotensin-converting enzyme in the blood serum was assayed with Friedland's and Silverstein's Technique in 24 female patients with untreated hyperthyroidism accompanying Graves-Basedow disease. Mean ACE activity was significantly higher in patients than that in the group of healthy individuals of the same age. Increased ACE activity noted in patients with Graves-Basedow disease may, therefore, indicated a significant role of renin-angiotensin-aldosterone system in the etiopathogenesis of hypertension in this disease.
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PMID:[Activity of angiotensin-converting enzyme in women with hyperthyroidism accompanying Graves-Basedow disease]. 133 53

The angiotensin I-converting enzyme (kininase II, ECA) is a membrane bound enzyme anchored to the cell membrane through a single transmembrane domain located near its carboxyterminal extremity. Secretion of ACE by the cell occurs most likely as a result of a posttranslational cleavage of the membrane anchor and intracellular region. The ACE molecule is organized into two large highly homologous domains, each bearing consensus sequences for zinc binding in metallopeptidases. Site directed mutagenesis allowed to establish that both domains bear in fact a functional active site, able to convert angiotensin I into angiotensin II and to hydrolyze bradykinin or substance P. The two active sites of ACE, however, do not display the same sensitivity to anion activation (the C terminal active site being more chloride activatable) and also differs in kinetic parameters for peptide hydrolysis. The C terminal active site can hydrolyze faster angiotensin I and substance P and the N terminal active site is able to perform a peculiar endoproteolytic cleavage of an in vitro substrate of ACE, the luteinizing hormone releasing hormone. Both active sites bind with a high affinity, competitive inhibitors but the Kd of the reaction can vary up to 10 between the two active sites. All together, these observations suggest that ACE contains two active sites, whose structure is not exactly identical. They may have a different substrate specificity, however this remains speculative at the present time. Concerning the regulation of ACE gene expression in man, population studies indicated that the large interindividual variability in plasma ACE levels is genetically determined. An insertion/deletion polymorphism located in an intron of ACE gene is associated with differences in the level of ACE in plasma and cells. The physiological and clinical implications of these observations is discussed.
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PMID:[Angiotensin converting enzyme (kininase II). Molecular and physiological aspects]. 133 89

Dried bonito (Katsuobusi), a Japanese traditional seasoning made of bonito muscle was hydrolyzed by various proteases and the inhibitory activity of the hydrolyzates for angiotensin I-converting enzyme (ACE) [EC 3.4.15.1] was measured. Among the digests, thermolysin digest showed the most potent inhibitory activity. Eight inhibitory peptides were isolated from the digest using HPLC. The amino acid sequences of inhibitory peptides were Ile-Lys-Pro-Leu-Asn-Tyr, Ile-Val-Gly-Arg-Pro-Arg-His-Gln-Gly, Ile-Trp-His-His-Thr, Ala-Leu-Pro-His-Ala, Phe-Gln-Pro, Leu-Lys-Pro-Asn-Met, Ile-Tyr, and Asp-Tyr-Gly-Leu-Tyr-Pro. By searching for the sequence homology in many proteins, four of them were found in the primary structure of actin. Asp-Met-Ile-Pro-Ala-Gln-Lys was obtained from the boiling water extract of dried bonito and this peptide was found in the primary structure of creatine kinase. Fragments of these peptides were prepared by further enzymatic digestion or chemical synthesis and their ACE-inhibitory activities were measured. Among them, Ile-Lys-Pro, Ile-Trp, Leu-Lys-Pro, and Leu-Tyr-Pro had higher inhibitory activity than their parental peptides. Ile-Lys-Pro suppressed the hypertensive activity of angiotensin I.
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PMID:Peptide inhibitors for angiotensin I-converting enzyme from thermolysin digest of dried bonito. 136 54

Angiotensin-converting enzyme inhibition with enalapril increases the number of glomeruli with juxtaglomerular cells and the number of cells in the afferent arteriole that express the renin gene and contain renin. However, renin release from these newly recruited renin-containing cells has not been demonstrated. Sodium depletion also has been shown to increase renal renin messenger RNA levels. The aim of these studies was to determine whether increases in renin secretion are a result of altered numbers of cells synthesizing/releasing renin or a change in the amount of renin release per cell, or both. Adult Wistar-Kyoto rats were treated with enalapril or sodium depleted and single cell renin secretion of enzymatically dispersed renal cortical cells was examined by reverse hemolytic plaque assay. Enalapril treatment increased the number of renin secreting cells by approximately 10-fold (P < 0.05). The newly recruited renin-secreting cells were not responsive to changes in extracellular calcium concentration or the presence of isoproterenol. At physiological (2.5 mM) extracellular calcium concentration, the amount of renin secreted per cell was approximately 2-fold greater (P < 0.05) when cells from enalapril-treated rats were compared to controls and sodium depletion increased both the number of renin-secreting cells and the amount of renin secreted by approximately 35% (P < 0.05). Angiotensin II (AII) inhibited the number of cells secreting renin in cortical cells prepared from enalapril-treated and control rats. In conclusion, angiotensin converting enzyme inhibition increased renin secretion predominantly by recruitment of additional renin-secreting cells and, to a lesser extent, by augmentation of the amount of renin released per cell. In contrast, sodium depletion increased renin secretion equally by both mechanisms. Newly recruited renin-secreting cells were not regulated by the extracellular calcium concentration or beta-adrenergic stimulation. Angiotensin II inhibited renin secretion directly by decreasing the number of individual cells releasing renin through a process which was independent of the extracellular calcium concentration.
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PMID:Effects of angiotensin converting enzyme inhibition, sodium depletion, calcium, isoproterenol, and angiotensin II on renin secretion by individual renocortical cells. 139 4

This study was designed to evaluate the role of neutral endopeptidase (NEP) in modulating the airway smooth muscle contraction induced by endothelin-1 in isolated segments of guinea-pig trachea. Endothelin-1 (10(-9)-10(-6) M) produced a concentration-dependent contraction that reached a maximum by 30 min. The NEP inhibitor leucine-thiorphan (10(-5) M) significantly increased the contractile response to endothelin-1. The addition of leucine-thiorphan to tracheal segments precontracted by 10(-9) and 10(-8) M endothelin-1 increased isometric tension by 181 +/- 65% (mean +/- 1 S.E.M.; P less than 0.05) and by 138 +/- 49% (P less than 0.05), respectively. In contrast, the kininase II inhibitor captopril and the peptidase inhibitors leupeptin and bestatin had no effect. Preincubation of endothelin-1 with 1 microgram recombinant human NEP decreased the contractile activity of endothelin-1 by 72 +/- 9%, whereas no effect was observed using heat-inactivated NEP. We conclude that NEP modulates endothelin-induced contraction of airway smooth muscle in the guinea-pig trachea.
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PMID:Neutral endopeptidase modulates endothelin-1-induced airway smooth muscle contraction in guinea-pig trachea. 143 68

In guinea pig plasma, bradykinin (BK) was degraded mainly to des-Arg1-BK by an aminopeptidase-like enzyme, which was inhibited by 2-mercaptoethanol. Besides this degradation, BK was also hydrolyzed by kininase I and kininase II from C-terminal end to des-Arg9-BK, des-Phe8-Arg9-BK and Arg-Pro-Pro-Gly-Phe ([1-5] BK). The formation of des-9-BK was strongly blocked by DL-2-mercaptomethyl-3-guanidinoethylthiopropanoic acid (MGPA) and that of des-8,9-BK and [1-5] BK was inhibited by captopril. When guinea pigs were pretreated with a cocktail of 2-mercaptoethanol, MGPA and captopril, intravenous administration of leukotriene (LT) C4 (10 nmol/kg) caused an increase in the levels of free kinin in the bronchial washings of guinea pigs. This increase was accompanied with the increase in glandular-kallikrein activity, which could be inhibited by aprotinin. As BK is reported to induce both bronchoconstriction and bronchial secretion, the increased free BK induced by LTC4 might enhance the effect of LTC4.
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PMID:Increase in the kinin levels in the bronchial washings after intravenous injection of leukotriene C4 in guinea pigs. 146 80

Since converting enzyme and kininase II are identical enzymes and probably influences both, the biosynthesis of Ang II and the metabolism of bradykinin we investigated the effects of bradykinin, desArg-bradykinin and some bradykinin antagonists (desArg[9]-Leu[8]-bradykinin, HOE S 890307) on the sympathetic outflow of pithed SHR or Brown-Norway-Rats before and after acute or chronic inhibition of the converting enzyme by ramipril. bradykinin increased dose dependently the noradrenaline and adrenaline release in particular when the converting enzyme was inhibited. DesArg-bradykinin caused a dose-dependent increase in adrenaline release only after converting enzyme inhibition. The bradykinin-antagonists led to an increase in adrenaline release during ramipril administration. The weak but significant stimulation of adrenaline release by the bradykinin antagonists after converting enzyme inhibition might be due to unspecific actions on the adrenal medulla possibly induced by histamine release from mast cells.
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PMID:Modulation of presynaptic sympathetic activity by kinins and related compounds: influence of converting enzyme inhibition. 146 84

The effect of kininase II inhibitor, enalapril, on the delivery of monoclonal antibody A7 to the targeted tumor was investigated using athymic mice bearing human colon cancer, SW1116. Enalapril alone, which enhances tumor vascular permeability through the kinin-generating cascade, did not increase the uptake of 125I-labeled A7 (125I-A7) in SW1116 due to the systemic hypotension induced by its inhibitory effect on angiotensin converting enzyme. However, with combined angiotensin II (AT-II) and enalapril treatment, a 2-fold increase in the accumulation of 125I-A7 was seen when compared to A7 alone. This marked increase was presumably due to increased tumor vascular permeability induced by enalapril combined with the absence of hypotension due to the actions of AT-II. This approach might be useful in radioimmunodetection and immunotargeting chemotherapy using monoclonal antibody.
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PMID:Enhanced tumor localization of monoclonal antibody by treatment with kininase II inhibitor and angiotensin II. 158 84

Extracts of wild garlic (Allium ursinum) and garlic (A. sativum) with defined chemical compositions were investigated for their in vitro inhibitory potential on 5-lipoxygenase (LO), cyclooxygenase (CO), thrombocyte aggregation (TA), and angiotensin I-converting enzyme (ACE). The inhibition rates as IC50 values of both extracts for 5-LO, CO, and TA showed a good correlation with the %-content of the major S-containing compounds (thiosulfinates and ajoenes) of the various extracts. In the 5-LO and CO test the garlic extracts are slightly superior to the wild garlic extracts whereas, in the TA test, no differences could be found. In the ACE test the water extract of the leaves of wild garlic containing glutamyl-peptides showed the highest inhibitory activity followed by that of the garlic leaf and the bulbs of both drugs. The comparative studies underline the usefulness of wild garlic as a substitute of garlic.
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PMID:Comparative pharmacological investigations of Allium ursinum and Allium sativum. 162 Jul 34

Angiotensin-converting enzyme (ACE, kininase II, EC 3.4.15.1) was quantified in selected areas of the rat brain by 3 different methods. The enzyme activity was quantified by an enzymatic assay in homogenates of discrete brain areas with the use of the artificial substrate hippuryl-His-Leu-[14C]glycine. Binding of the specific ACE inhibitor [125I]351A was quantified after incubation of thin brain sections followed by quantitative autoradiography with comparison to [125I]standards. The antigenic sites of the enzyme were quantified by immunoautoradiography, using a polyclonal antibody to ACE in combination with [125I]protein A followed by quantitative autoradiography. There was a good correlation between the ACE activity, as determined by the quantitative enzymatic method, and both the enzyme inhibitor binding and the [125I]protein A binding, as determined by quantitative autoradiography, in brain areas and in anterior and posterior lobes of the pituitary gland. The present data demonstrate that ACE activity and ACE binding can be quantified in discrete tissue areas with different methods in a variety of conditions and with a high degree of accuracy.
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PMID:Comparative quantification of rat brain and pituitary angiotensin-converting enzyme with autoradiographic and enzymatic methods. 165 Feb 74


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