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)

Albumin and immunoglobulin G (IgG) show increased visible fluorescence in diabetic patients, IgG fluorescence being correlated with the presence of diabetic retinopathy. Captopril, an angiotensin converting enzyme (ACE) inhibitor, has free radical scavenging ability, attributable to its thiol group. We compared the scavenging effect of captopril (at doses between 0.5 and 100 microM) with perindoprilat, enalapril and enalaprilat (ACE inhibitors without scavenging ability) and two thiol-containing compounds, mercaptopropionylglycine (MPG) and N-acetylcysteine (NAC) (scavengers with no effect on ACE). Three systems were used to generate visible fluorescence in albumin and IgG; glycation, exposure to copper/hydrogen peroxide and gamma radiation. All three thiol-containing compounds inhibited fluorescence development in IgG and albumin, when fluorescence was generated by glycation or gamma radiation. Other ACE inhibitors had no effect with IgG. Enalapril and perindoprilat showed less effect than captopril with albumin; enalaprilat had no effect. No compound had any effect on fluorescence generation by copper/hydrogen peroxide. Captopril may have an additional antioxidant effect compared to other ACE inhibitors.
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PMID:Captopril inhibits the fluorescence development associated with glycation of proteins. 152 7

Thiyl free radicals have been shown to react with polyunsaturated fatty acids via abstraction of bisallylic hydrogen, forming pentadienyl radicals, and via addition to the double bonds. In the absence of oxygen, the latter pathway leads to regeneration of thiyl radicals through beta-elimination or "repair" of the adduct radicals by thiols. In the presence of oxygen, fixation of thiyl-induced damage occurs through reaction of O2 with the pentadienyl radical (yielding conjugated dienyl peroxyl radicals) and also with the thiyl-to-double bond adduct radical. A quantitative reaction scheme evaluated from these data considers abstraction, addition, rearrangement, and repair reactions, and the evaluation of rate constants for the individual steps. Absolute rate constants have been measured, in particular, for reactions of thiyl free radicals from glutathione, cysteine, homocysteine, N-acetylcysteine, cysteine ethyl ester, penicillamine, captopril, mercaptoethanol, and dithiothreitol with polyunsaturated fatty acids (PUFAs) ranging from 18:2 to 22:6, and the lipids trilinolein and trilinolenin. The rate constants for hydrogen abstraction were found to be typically of the order of 10(7) mol-1 dm3 s-1 and to increase with increasing lipophilicity of the attacking thiyl radical. Thioperoxyl radicals, RSOO., were found to be rather unreactive toward PUFAs, in contrast to the isomer sulfonyl radicals, RSO2., which not only abstract hydrogen from the bisallylic methylene groups of the PUFAs (although only at relatively small yield) but also readily add to the PUFA double bonds (major pathway). Specific information was obtained on the optical properties of the thiyl radical derived from the ACE inhibitor captopril, CpS. (lambda max = 340 nm, epsilon = 460 +/- 50 mol-1 dm3 cm-1), and its conjugate disulfide radical anion (CpS:.SCp) (lambda max = 420 nm).
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PMID:Oxidation of polyunsaturated fatty acids and lipids through thiyl and sulfonyl radicals: reaction kinetics, and influence of oxygen and structure of thiyl radicals. 173 11

As chronic hypertension shifts the lower limit of cerebral blood flow (CBF) autoregulation to higher pressure levels, we studied the effects of the angiotensin converting enzyme (ACE) inhibitor, perindopril on mean arterial pressure (mean BP), basal CBF, and CBF autoregulation in awake renovascular hypertensive (2 kidneys, 1 clip model) and spontaneously hypertensive rats (SHR). Blood pressure was measured via a chronically implanted arterial cannula and CBF by hydrogen clearance. Chronic renovascular hypertension, like spontaneous hypertension, caused a marked shift in the lower limit of CBF autoregulation but did not alter basal CBF. In SHR, acute administration of perindopril did not diminish CBF in spite of the fact that BP fell to a level below the lower limit of CBF autoregulation (determined by hypotensive hemorrhage). Chronic treatment of renovascular hypertensive rats with perindopril normalized BP and restored CBF autoregulation.
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PMID:Effects of the angiotensin I converting enzyme inhibitor perindopril on cerebral blood flow in awake hypertensive rats. 204 13

The acute effects of various antihypertensive agents on cerebral blood flow and mean arterial pressure (MAP) were studied in anesthetized (amobarbital 100 mg/kg) spontaneously hypertensive rats. Cerebral blood flow in the cortex and thalamus was measured by the hydrogen clearance method before and during a 60-min i.v. infusion of calcium antagonist (nifedipine), angiotensin converting enzyme inhibitor (captopril) or beta-blocker (propranolol). Nifedipine, 30 or 150 micrograms/kg per h, decreased dose dependently the MAP by 20 or 31%, and concomitantly increased cortical blood flow by 28 or 74%, and thalamic blood flow by 51 or 64%, respectively. Captopril, 10 or 100 mg/kg per h, decreased MAP by 7 or 14%, but changed cerebral blood flow minimally. In contrast, propranolol, 1.0 or 5.0 mg/kg per h, decreased MAP by 13 or 11%, with a concomitant reduction of cortical and thalamic blood flow by 20 or 15 and 33 or 37%, respectively. It is concluded that the changes in cerebral blood flow in response to hypotension are varied by antihypertensive drugs depending on the direct or indirect effect of the drugs (dilatation or constriction) on cerebral vessels. Nifedipine seems to dilate while propranolol constricts cerebral vessels.
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PMID:Acute effects of antihypertensive agents on cerebral blood flow in hypertensive rats. 219 21

N-(2-mercaptopyridyl-3-formyl)-N-alkyl glycine I1-8) were synthesized by the condensation of 2-mercaptopyridyl-3-formyl chloride with ethyl N-alkyl glycinate followed by hydrolysis. The corresponding disulfides (II1-7) were obtained by the oxidation of compounds I1-7 with hydrogen peroxide (1%) in weak alkali medium below 10 degrees C. In preliminary tests, some compounds showed inhibitory activity of ACE in vitro.
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PMID:[Synthesis of N-(2-mercaptopyridyl-3-formyl)-N-alkyl glycine and the corresponding disulfides]. 228 59

This simple, accurate, and reproducible colorimetric method for determining the activity of angiotensin-I converting enzyme is based upon colorimetry of the quinoneimine dye produced from the substrate p-hydroxyhippuryl-L-histidyl-L-leucine by action of this enzyme through the following series of reactions. The enzyme acts on the substrate to yield p-hydroxyhippuric acid and L-histidyl-L-leucine. The former is then hydrolyzed in the presence of hippuricase to produce p-hydroxybenzoic acid and glycine. Finally, oxidative coupling of p-hydroxybenzoic acid with 4-aminoantipyrine is catalyzed by peroxidase in the presence of hydrogen peroxide, producing a quinoneimine dye, the concentration of which is measured at its absorbance maximum at 505 nm to evaluate the activity of ACE. The Km value for the above-mentioned substrate is 0.32 mmol/L, the optimum pH is 8.3. Results by the present method and Cushman and Cheung's method (Biochem. Pharmacol. 20: 1637, 1971) correlate closely (r = 0.986). The within-run CV is 2.93%.
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PMID:Colorimetry of angiotensin-I converting enzyme activity in serum. 627 20

Presentation of drugs most worthy of interest in autumn 1995. Among these, the ACE inhibitors, the HMGCOA inhibitors, the Proton Pump inhibitors, the serotoninergics used against depression and migraine, the endobronchial corticoids and finally the ASA. Review of their successes, failures and uncertainties.
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PMID:[Leading drugs in 1995: success, failures and uncertainties]. 748 Dec 49

The affinity of three substrates for the intestinal peptide carrier is explained based on their three-dimensional (3D) structural data. The kinetic transport parameters of three ACE-inhibitors, enalapril, enalaprilat, and lisinopril, have been determined in an in vivo system using rat intestine. The observed kinetic transport parameters (+/- asymptotic standard error) of enalapril are: 0.81 (+/- 0.23) mM, 0.58 (+/- 0.37) mumol/h per cm2, and 0.56 (+/- 0.04) cm/h for the half-maximal transport concentration (KT), the maximal transport flux (Jmax) and the passive permeability constant (Pm). Enalaprilat was transported by passive diffusional with a Pm of 0.51 (+/- 0.04) cm/h. For lisinopril the kinetic transport parameters were 0.38 (+/- 0.19) mM, 0.12 (+/- 0.07) mumol/h per cm2, and 0.18 (+/- 0.02) cm/h for KT, Jmax, and Pm, respectively. The affinity of the ACE-inhibitors for the intestinal peptide carrier has been evaluated based on their ability to inhibit the transport rate of cephalexin. The inhibition constants (Ki) of enalapril, enalaprilat and lisinopril were 0.15, 0.28 and 0.39 mM, respectively. 3D structural analysis of lisinopril using molecular modelling techniques reveals that intramolecular hydrogen bond formation is responsible for decreased carrier affinity.
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PMID:Molecular mechanism for the relative binding affinity to the intestinal peptide carrier. Comparison of three ACE-inhibitors: enalapril, enalaprilat, and lisinopril. 779 53

Cu,Zn-superoxide dismutase plays an important role in protecting cells from oxygen toxicity by catalyzing the dismutation of superoxide anion into hydrogen peroxide and oxygen. In Saccharomyces cerevisiae Cu,Zn-superoxide dismutase is coregulated with copper-thionein by copper via the transcription factor ACE 1. We demonstrate here that presence of AgNO3 in the culture medium leads to a five times increase of Cu,Zn-superoxide dismutase mRNA, with a concomitant six times decrease of the enzyme activity. Susceptibility of yeast to silver was apparently inversely related to Cu,Zn-superoxide dismutase activity. From silver-treated yeast a Cu,Zn-superoxide dismutase with impaired dismutase function was purified and was shown to contain silver, which was located to the copper site. These data suggest that Cu,Zn-superoxide dismutase may play an additional direct role in the defense of S. cerevisiae against metal stress by functioning as metal chelator.
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PMID:Purification and characterization of Ag,Zn-superoxide dismutase from Saccharomyces cerevisiae exposed to silver. 792 83

Utilization of highly enriched preparations of steroidogenic Leydig cells have proven invaluable for studying the direct effects of various hormones and agents on Leydig cell function in vitro. However, recent work indicates that isolated Leydig cells are often subjected to oxygen (O2) toxicity when cultured at ambient (19%) oxygen concentrations. Because intracellular antioxidants play an important role in protecting cells against oxygen toxicity, we have investigated the intracellular antioxidant defense system of isolated Leydig cells. The cellular levels of several antioxidants including catalase, glucose-6-phosphate dehydrogenase (G-6-PDH), superoxide dismutase (SOD) of the Cu/Zn & Mn variety, glutathione peroxidase, glutathione reductase and total glutathione were quantitated using enriched populations of Leydig cells isolated from adult male guinea pig testes. Compared to whole testicular homogenates, Leydig cells contained significantly (P < 0.01) less G-6-PDH, total SOD, glutathione reductase and total glutathione, but significantly (P < 0.001) more glutathione peroxidase. Compared to hepatic values previously reported in the guinea pig, Leydig cells contain nearly 400 times less catalase, about 14 times less glutathione peroxidase and almost 11 times less glutathione reductase. Since G-6-PDH and glutathione reductase are both necessary to regenerate reduced glutathione (GSH) which couples with glutathione peroxidase to breakdown hydrogen peroxide (H2O2) under normal conditions, it is plausible that the oxygen toxicity observed in isolated Leydig cells is due to the intracellular accumulation of H2O2.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The antioxidant defense system of isolated guinea pig Leydig cells. 810 85


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