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:3.4.23.5 (cathepsin D)
4,130 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aim of this study was to develop a method for the measurement of renin activity in small tissue samples obtained from rat brains by the micropunch technique and to investigate the activity of brain renin in spontaneously hypertensive rats. The assay satisfied sensitive and specificity requirements. Angiotensin I was generated at a pH of 6.0; complete recovery of angiotensin I and kinetic studies supported the specificity of the method. Angiotensinase and cathepsin D-like acid protease activity were measured in parallel with renin. Renin was present in all brain regions studied and decreased with the age of the animals. An increased activity of renin was measured in several nuclei of the brain stem and in the neurohypophysis of young hypertensive rats when compared with age-matched normotensive control animals. These differences disappeared in older rats. There was a dissociation between renin and cathepsin D-like acid protease activity. No correlation existed between the distribution of renin and angiotensinase activity. The increased renin activity in brain stem nuclei of spontaneously hypertensive animals is in agreement with previous findings that the brain renin-angiotensin system contributes to the maintenance of high blood pressure in these rats.
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PMID:A micromethod for the measurement of renin in brain nuclei: its application in spontaneously hypertensive rats. 628 32

There are two types of enzymes in tissues leading to angiotensin formation: a) those resulting in the formation of angiotensin I, such as renin and cathepsin D, the presence of which is now well established for brain tissue and b) Those leading to the direct formation of angiotensin II without the angiotensin I step, such as cathepsin G and tonin. Recent findings concerning tonin, a serine protease, are described: a) 80% of its amino acid sequence, b) its different characteristics from other serine proteases, from renin, cathepsin D and the angiotensin I converting enzyme, c) the activation of inactive renin, d) its involvement in the 1K-1C hypertensive rats, e) the demonstration of its presence in the distal tubular cells of the rat kidney, and finally, f) its presence in urine and the influence of age and of sodium intake on its urinary excretion.
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PMID:Extrarenal angiotensin-forming enzymes. 631 65

Vascular renin-like activity was studied in the aortas and the cerebral microvessels of Sprague-Dawley rats and in the aortas of spontaneously hypertensive rats. Methods were employed to maximize detection of tissue renin and to simultaneously minimize contamination of that activity by either plasma renin or nonspecific proteases capable of angiotensin I generation. To this end, renin activity was measured near its pH optimum; plasma renin was eliminated by nephrectomy; and nonspecific proteases such as cathepsin D were either inhibited by proteolytic blockers or removed by chromatography over immobilized bovine hemoglobin. Aortic vascular renin-like activity was detected in rats not subjected to nephrectomy and could be inhibited by preincubation of samples with antimouse renin antibody shown to cross-react and inhibit rat plasma renin activity. Furthermore, vascular renin-like activity disappeared after nephrectomy in parallel with the disappearance of plasma renin activity. In the absence of contaminating enzymatic activities, no tissue renin-like activity could be demonstrated in either aortas or cerebral microvessels of Sprague-Dawley rats or in aortas of spontaneously hypertensive rats.
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PMID:Absence of renin-like activity in rat aorta and microvessels. 635 79

Renin and cathepsin D were purified by seven-step procedures involving five steps common to both enzymes. These common five steps were extraction of freeze-dried kidney powder in 30% methoxyethanol-water, diethylaminoethyl-cellulose (DEAE-cellulose) batch absorption and elution, pepstatin-aminohexyl-Sepharose chromatography, Sephadex G-100 chromatography, and DEAE-cellulose chromatography. The renin component was purified further by passage through an anti-rat spleen cathepsin D immunoglobulin G-Sepharose (IgG-Sepharose) column followed by carboxymethyl-Sephadex (CM-Sepharose) chromatography which separated two renin components. Cathepsin D activity obtained by the fifth step was purified by passage through an anti-rat kidney renin IgG-Sepharose column followed by DEAE-Sephacel chromatography which separated three cathepsin D components. The homogeneity of renin and cathepsin D preparations was demonstrated by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The two components of renins showed molecular weights of 42 000 and 36 000 by gel filtration and 38 000 and 36 000 by SDS gel electrophoresis, respectively. They showed isoelectric points of 5.35 and 5.65 by electrofocusing in 5% polyacrylamide gels. Their optimum pHs of enzyme activity were 6.5 as determined by using nephrectomized rat plasma as a substrate. Their specific angiotensin I (Ang I) generation activities were 158 and 146 micrograms of Ang I (microgram of protein)-1 h-1, respectively, which correspond to 1100 and 1020 Goldblatt units (mg of protein)-1 h-1. The three cathepsins showed molecular weights of 41 000, 43 000, and 41 000 by gel filtration and 46 000, 45 000, and 46 000 by SDS gel electrophoresis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Rat kidney renin and cathepsin D: purification and comparison of properties. 636 Feb 7

A synthetic tetradecapeptide, H-Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu-Val-Ile-His-Ser-OH, which corresponds to the 13 amino terminal residues of human angiotensinogen plus a carboxy terminal serine to replace a suggested site of carbohydrate attachment, has been shown to be a good substrate for human kidney renin. At pH 7.2 and 37 degrees C the KM or Michaelis constant was 8.4 +/- 2.9 microM, and the VM or velocity at infinite tetradecapeptide concentration was 11.3 +/- 2.4 mumol angiotensin I made per hour per milligram renin. The tetradecapeptide was highly resistant to cleavage by mouse submaxillary renin. The tetradecapeptide was also slowly cleaved by human liver cathepsin D, by rabbit lung angiotensin-converting enzyme, and by reconstituted human serum, but did not yield angiotensin I. Thus, this synthetic renin substrate should permit more specific measurement of human kidney renin activity.
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PMID:Renin cleavage of a human kidney renin substrate analogous to human angiotensinogen, H-Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu-Val-Ile-His-Ser-OH, that is human renin specific and is resistant to cathepsin D. 638 71

We developed new sensitive direct radioimmunoassay for human plasma renin. Renin was purified from Haas' preparation utilizing a pepstatin-C6-Sepharose affinity chromatography. Antiserum, prepared by immunizing rabbits with the purified renin, was used for the direct radioimmunoassay at a final dilution of 1:30,000. The antibody was specific for human renal and plasma renin, but did not cross-react with cathepsin D, trypsin, or renins of mouse, dog, and rat. Radioimmunoassay was performed by the double antibody technique using the delayed tracer addition method. In this method, a standard curve was obtained over a range from 0.2 to 8.0 ng/ml. The values from our assay correlated well with total renin activity measured as the generation rate of angiotensin I after trypsin activation (r = 0.78, p less than 0.01), but correlated weakly with active renin activity. This finding disclosed that both active and inactive renin were detected by this method. In normal participants, plasma renin concentration determined by direct radioimmunoassay was increased by standing and furosemide injection. The plasma renin concentration determined by direct radioimmunoassay of patients with essential hypertension (0.7 to 1.7 ng/ml) was not significantly different from values in normal controls (0.8 to 1.9 ng/ml). The values were higher in patients with renovascular hypertension (1.6 to 2.7 ng/ml), malignant hypertension (2.8 to 3.4 ng/ml) and Bartter's syndrome (1.8 to 2.5 ng/ml), but lower in patients with primary aldosteronism (0.4 to 0.8 ng/ml) than in normal controls. This newly developed radioimmunoassay for human renin was sensitive enough to estimate the levels of renin in plasma of patients with low renin hypertension. It provides a new tool for the understanding of the renin-angiotensin system under various clinical conditions.
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PMID:A new sensitive direct radioimmunoassay for human plasma renin and its clinical application. 638 35

Secretory vesicles purified from the neural and intermediate lobes of the bovine pituitary contain acidic endopeptidases which are capable of converting renin tetradecapeptide (RTD) substrate to Angiotensin I (AI). Preliminary characterization of the neurosecretory vesicle (NSV) endopeptidase showed that it had a pH optimum of 4.0, and unlike renin was inactive at pHs greater than 6.0. It is inhibited by 10(-6) M pepstatin A, but not by PMSF, leupeptin, PMBS, or the specific renin inhibitor H-142. This NSV endopeptidase differed from cathepsin D in that it was unable to degrade alpha-casein, but was quite active in generating AI from RTD (Vmax = 5 moles/g protein/hour). No enzyme activity that could convert AI to Angiotensin II could be detected in the NSVs suggesting that the acidic endopeptidase is involved in processing neurosecretory vesicle proteins other than those associated with the renin angiotensin system in the brain.
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PMID:Angiotensin I-generating acid endopeptidase activity in neurosecretory vesicles isolated from bovine pituitary. 639 22

A new inhibitor of human renin (H. 189) is described. It is a decapeptide analogue of human renin substrate with the amino acid, statine, substituted for leucine in the scissile bond. Its inhibitory potency as shown by IC50 is 1.0 X 10(-8) M with human plasma renin and 1.5 X 10(-8) M with baboon plasma renin. It is less effective with dog and rat renin, but its inhibitory potency with human renin is similar to that of another inhibitor of ours (H. 142) having a reduced isostere in the scissile bond. H. 189 has some inhibitory effect on cathepsin D (IC50 6.5 X 10(-5) M) but H. 142 has no discernible effect. Pepstatin, on the other hand, was highly effective against cathepsin D (IC50 1.2 X 10(-8) M). H. 142 and H. 189 were infused intravenously at 10 mg/kg/h in four anaesthetized salt-deplete baboons (Papio hamadryas). The activity of renin in plasma decreased markedly as did the circulating concentration of its products, angiotensin I and angiotensin II.
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PMID:New inhibitors of human renin tested in vitro and in vivo in the anaesthetized baboon. 639 31

We designed aldehyde derivatives of small peptides representing the C-terminal portion of angiotensin I sequence as an inhibitor of human renin. Among compounds that we synthesized, benzyloxycarbonyl (Z)-Phe-His-Leucinal (compound V), Z-Pro-Phe-His-Leucinal (Compound IV) and Z-[3-(1'-naphthyl)Ala]-His-Leucinal (compound VII) markedly inhibited human renin (IC50, 7.5 X 10(-7), 3.2 X 10(-7) and 8.0 X 10(-8) mol/l, respectively). Compound VII was shown to be noncompetitive (Ki = 2.4 X 10(-7) mol/l). It did not inhibit either cathepsin D or pepsin. Compound V had slight or no inhibitory effect at the concentration of 10(-5) mol/l on six animal renins except for monkey and rabbit renins. Results obtained show that these aldehyde compounds are highly selective and species specific inhibitors for human and monkey renins.
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PMID:Highly potent and specific inhibitors of human renin. 642 31

In order to help clarify the role of the renin-angiotensin system in the evolution of the post-hemorrhagic circulatory shock syndrome, captopril, a potent inhibitor of the conversion of angiotensin I to angiotensin II, was infused into a hemorrhagic shock model in the cat. The hemorrhage protocol had arterial blood withdrawn until a mean arterial blood pressure (MABP) of 40 mm Hg developed. Oligemia was maintained for a period of 2.5 hr, after which time, all remaining shed blood was reinfused and the cats observed for an additional 2 hr. Coincident with the large reduction in MABP, superior mesenteric artery flow (SMAF) was similarly reduced as recorded by a noncannulating electromagnetic flow probe fitted around the artery. Post-oligemic plasma activities of cathepsin D (CD) and alkaline phosphatase (AP) were elevated 11-fold and 3-fold respectively; intestinal morphological damage was graded at 2.8 +/- 0.6 on a 0-4 scale of increasing severity (control: 0.03 +/- 0.02). Captopril was administered at an initial priming dose of 0.5 mg/kg followed by a continuous infusion of 0.5 mg/kg/hr. Improved post-reinfusion maintenance of MABP and SMAF was noted. Plasma elevations in enzyme activity were more moderate: 8-fold for CD, 1.5-fold for AP. Intestinal morphologic damage was graded at 2.5 +/- 0.3. Blockade of angiotensin II formation by captopril thus demonstrated beneficial effects on post-oligemic hemodynamic status and on the degree of cellular enzyme release without significant improvement in intestinal morphology.
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PMID:Captopril and the intestinal response to hemorrhagic shock. 675 18


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