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:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A compound containing cyclostatine ES-6864 (N-[(2R)-3-morpholinocarbonyl-2-(1-naphthylmethyl)propionyl]-(4-th iazolyl)- L-alanyl-cyclostatine-(2-morpholinoethyl)amide) was found to be a competitive inhibitor of human renin with an inhibitory constant (Ki) value of 7.3 x 10(-9) M. The compound was also potent against monkey renin but was less effective against renins from pig, goat, dog, rabbit and rat. ES-6864 did not inhibit cathepsin D, pepsin, urinary kallikrein, angiotensin converting enzyme, trypsin and chymotrypsin at a concentration of 10(-5) M. ES-6864 also inhibited the tissue renin-like activity from dog tissues with IC50 values of 10(-7)-10(-8) M in vitro. Oral administration of ES-6864 at 30 mg/kg to conscious, sodium-depleted marmosets produced a significant blood pressure reduction and a significant inhibition of plasma renin activity, which persisted for 6 hours. Plasma concentration of ES-6864 reached a maximum of 1.2 micrograms/ml at 1 hour after an oral administration. Oral administration of ES-6864 to hog renin-infused rats produced dose-related decreases in blood pressure. The results demonstrate that ES-6864 is an orally active renin inhibitor with high potency and specificity for human renin. Thus, ES-6864 is a candidate compound for development of renin inhibitors that can be used clinically.
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PMID:[In vitro and in vivo inhibition of renin by a thiazolylalanyl cyclostatine derivative]. 251 1

We studied the functional significance of the binding of angiotensin-II (AII) to human placentas. Human trophoblastic cell suspensions were prepared by trypsin digestion of minced tissue. Cell incubations with increasing doses of [125I](SAR1)AII, ranging from 0.01-2.5 nmol/L, were carried out for 20 min at 37 C. The results indicated the presence of specific low capacity [4300 +/- 1300 (+/- SE) sites/cell], high affinity (Kd = 0.38 +/- 0.06 nmol/L) binding sites for [125I](Sar1)AII. This binding was specific for AII analogs. When placental cells were preloaded with 40 microCi/mL [3H]myoinositol for 2 h at 37 C, AII stimulation resulted in a dose-dependent increase in inositol phosphate (InsP) production [EC50 = 1.4 +/- 0.4 (+/- SE) nmol/L], as measured by ion exchange chromatography. (Sar1)AII also stimulated InsP production, with an EC50 of 0.3 +/- 0.2 nmol/L. AII-stimulated production of InsP was completely blocked by the antagonist (Sar1,Ala8)AII. AII also stimulated human placental lactogen release from trophoblastic cells in a dose-dependent fashion. The EC50 was 18 +/- 9 pmol/L, and the stimulation was blocked by (Sar1,Ala8)AII, as found for AII-stimulated InsP production. These results suggest that stimulation of human placental lactogen release by AII may be mediated by activation of phospholipase-C, which, in turn, produces phosphoinositide breakdown. The results, therefore, provide evidence of a physiological role for the renin-angiotensin system within the human placenta.
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PMID:Angiotensin II stimulates both inositol phosphate production and human placental lactogen release from human trophoblastic cells. 254 60

Enzymatically inactive renin (IR) is the predominant circulating form of renin. Sympathetic activity may influence plasma renin activity (PRA) by regulation of the conversion of IR to active renin (AR, PRA). It has been demonstrated previously that beta blockade lowers PRA at least partly through inhibition of this conversion process. The authors hypothesized that beta blockade and intrinsic sympathomimetic activity (ISA) would have opposing effects on production of AR from its inactive precursor. Eighteen primary hypertensives (12 male, 6 female, mean age 57.7 +/- 2.7) were entered in a placebo-controlled, double-blind crossover study of the effects of equipotent doses of pindolol and propranolol on mean +/- SEM systolic BP, diastolic BP, heart rate, active renin (AR), total renin (TR), inactive renin (IR), and % AR/TR. Drug dose was titrated to achieve a goal DBP of 90 mmHg or less. Active renin was defined as the rate of generation of angiotensin I in 37 degrees C plasma at pH 5.7. Total renin was determined by preincubation of plasma aliquots with 1.5 mg/mL trypsin in the presence of 5 mM benzamadine for one hour at -4 degrees C prior to assay of renin activity. Inactive renin was calculated as TR minus AR. The BP responses achieve by dose titration of propranolol and pindolol were virtually identical at rest, indicating equivalent depressor effects of the two beta blockers. Heart rate and active renin were, however, lowered to a much greater extent with propranolol as compared with pindolol. The lack of significant pindolol-induced fall in % AR/TR suggests that this drug has little net effect on the formation of AR from IR.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Intrinsic sympathomimetic activity counteracts beta-blocker inhibition of renin activation. 256 12

The physiological role of inactive renin, especially the question of whether and how a conversion to active renin takes place in vivo, remains controversial. In order to show the dynamic alterations from inactive to active renin following acute ACE-inhibition, both forms of renin were investigated in both renal veins and the peripheral circulation of 20 patients with essential hypertension and 20 patients with renovascular hypertension before and 1 h after 25 mg of captopril. Active and inactive renin were determined indirectly as plasma renin activity (PRA, unit: ng/ml x h). In vitro activation of inactive renin was achieved with trypsin (1 mg/ml plasma), followed by a further determination of PRA (= total renin). Subtraction of the active renin from the total renin yields the amount of inactive renin. In patients with essential hypertension, the mean values of active renin increase equally in both renal veins (1.4 and 1.3 before, 1.9 and 1.8 after captopril) and the peripheral circulation (0.9 and 1.3) (p less than 0.002), whereas the inactive renin decreases correspondingly. Renal veins: 7.6 and 8.2 before, 7.2 and 7.6 after captopril; peripheral circulation: 7.7 before and 7.0 after captopril (p less than 0.05). In all patients with renovascular hypertension, there is basally a marked lateralization of active renin (6.4 vs 3.5; p less than 0.01) and inactive renin (20.5 and 18.9, p less than 0.03) towards the side of the ischemic kidney. After captopril, the values for total renin and active renin increase (p less than 0.001), and the side difference for active renin becomes still more pronounced (33.0 vs 14.2; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Conversion of inactive renin to active renin following acute angiotensin converting enzyme inhibition in essential hypertension and renovascular hypertension]. 265 7

Venous occlusion of the left arm in consenting men was induced for 10 or 20 min to stimulate local fibrinolytic and other proteases, thereby favouring the conversion of prorenin to renin. Using the two techniques cryoactivation and tryptic activation, we found that plasma active renin increased significantly after such occlusion (10 and 20 min) while prorenin rose more convincingly and progressively from 10 to 20 min. The renin increase can be partially attributed to hemoconcentration, but in vivo production and (or) local activation of prorenin to renin cannot be excluded. The prorenin rise can apparently be attributed to local extrarenal production, and not to hemoconcentration or influx, since it was progressive and neither prorenin nor renin levels were raised at all in blood circulating outside the occluded arm. Prekallikrein and plasminogen levels were elevated in occlusion plasmas, but responsibility of these enzyme systems for any enhanced activation of prorenin was not established. The trypsin inhibitory capacity was also elevated, increasing the requirement of trypsin to achieve optimal activation of prorenin, but not changing the prorenin estimate itself. Thus, prorenin appears to be released extrarenally, within the vasculature of an occluded arm, while in vitro evidence suggests that the mechanisms for its activation were stimulated. The importance of such extrarenal production and activation of prorenin for renin production under other physiological or pathophysiological conditions remains to be determined.
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PMID:Extrarenal production and activation of human plasma prorenin: the evidence after venous occlusion. 265 95

Plasma inactive renin (IRA) were assayed through open heart surgery by trypsin treatment in twenty-two patients. Postoperatively plasma renin activities and IRA increased, remarkably in IRA, however total renin activities were lesser than plasma renin activities during extracorporeal circulation. From the results of addition of 125I-angiotensin I before trypsin treatment, the presence of unknown enzyme was assumed, which was activated by trypsin and catalyzed angiotensin I in extracorporeal circulation. Bacterial enzyme, thermolysin, also activated plasma inactive renin, more stably until 60 min at 0-37 degrees C than trypsin. By trypsin, activities were in peaks at 1 min and gradually decreased thereafter. Conclusively we could assess the superiority of thermolysin treatment over trypsin treatment.
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PMID:[Assessment of plasma inactive renin by trypsin and thermolysin treatment during open heart surgery]. 266 Feb 9

To clarify contradicting observations on the identity of inactive renin and prorenin, inactive renin was completely purified from native human chorion laeve and the culture medium of human chorion cells. A 720,000-fold purification with 14% recovery was achieved from chorion laeve in 6 steps, including immunoaffinity chromatography on a monoclonal antibody to human renin coupled to Protein A-Sepharose CL-4B. A 3,100-fold purification with 40% recovery was achieved from chorion culture medium in 4 steps, including immunoaffinity chromatography. Inactive renin purified from the two different sources migrated as a single protein band with the same molecular weight of 47,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and consisted of multiple components that could be resolved by isoelectric focusing. Both had the same pI values which shifted downward upon activation by trypsin; however, relative peak heights were different between the two preparations. The purified inactive renin from chorion laeve was completely inactive and did not bind to pepstatin-aminohexyl-Sepharose; however, that from chorion culture medium was partially active and completely bound to the pepstatin gel, indicating that each molecule is partially activated. Trypsin-activated inactive renins from both sources were identical with human renal renin in terms of pH optimum and Km. Specific activities of trypsin-activated inactive renin from chorion laeve and chorion culture medium were 529 Goldblatt units/mg of protein and 449 Goldblatt units/mg of protein, respectively. Amino acid sequence analysis of both of the purified inactive renin preparations demonstrated a leucine residue at the amino terminus. The sequence of 11 additional amino acids was identical in both and agreed with that predicted from the base sequence of the renin gene. These findings indicate that preprorenin is converted to prorenin following removal of a 23-amino acid signal peptide and that the native inactive renin, whose amino acid sequence commences with Leu-Pro-Thr..., is prorenin.
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PMID:Pure human inactive renin. Evidence that native inactive renin is prorenin. 267 Sep 24

Trypsin cleaved plasma angiotensinogen with apparent first-order kinetics and generated an angiotensin I (Ang I) immunoreactive material. Size exclusion high-performance liquid chromatography (HPLC) of rat plasma proteins demonstrated that the Ang I immunoreactive material was formed in those fractions which contained angiotensinogen. The Ang I immunoreactive material was higher in nephrectomized rat plasma than normal plasma, in accordance with the higher angiotensinogen concentration. These findings indicated that angiotensinogen could be the source of the Ang I immunoreactive material. Purification of the Ang I immunoreactive material by cation-exchange chromatography followed by reverse-phase HPLC demonstrated an elution pattern close to that of human tetradecapeptide. The purified Ang I immunoreactive material was cleaved by pure mouse submandibular renin to Ang I, exclusively. Incubation at 37 degrees C of the Ang I immunoreactive material with plasma partially destroyed the angiotensin immunoreactive material. These findings demonstrated that the angiotensin immunoreactive material was an Ang I containing tetradecapeptide (TDP)-like peptide, unstable during a renin incubation step, leading to erroneous values for plasma inactive renin if not removed. The Ang I immunoreactive material was removed by cation-exchange chromatography of trypsin-activated plasma allowing for a determination of inactive renin. The presence of inactive renin in plasma from normal and nephrectomized rats was confirmed, and identified by neutralization and immunoprecipitation with antirenins. These findings should enable us to develop a routine assay for plasma inactive renin in rat plasma.
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PMID:On the measurement of inactive renin in rat plasma: activation by trypsin generates interfering tetradecapeptide-like material and destroys angiotensinogen. 267 Nov 59

Cultured mouse myeloma cells were transfected with expression vectors encoding the aspartyl proteinase, human renin. The full construct, encoding the renin precursor prorenin, allows transfected cells to secrete the enzymically inactive pro-protein. Activity is detectable only following trypsin treatment which mimics the physiological activation step. Accordingly, it appears that myeloma cells do not contain detectable levels of an appropriate activating proteinase. However, when these cells are transfected with a construct from which the pro-peptide coding sequence has been deleted, they secrete an apparently fully active enzyme which is indistinguishable from mature renin. We conclude that expression of the pro-peptide is not necessary to allow correct folding of the molecule and its passage through the secretory pathway.
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PMID:The pro-peptide is not necessary for active renin secretion from transfected mammalian cells. 267 96

Our previous work has shown that pure hog renin, when injected into one-kidney, one-clip hypertensive rabbits elicits not only antirenin antibodies but also antibodies to what appears to be an altered form of renin (antigen M). Antiantigen M stains the cytoplasm of smooth muscle cells and certain other cells in tissues of normal and hypertensive rabbits. We now report studies in which pure 125I hog and rabbit renin have been infused into hypertensive rabbits for seven-day periods and the tissues subsequently examined for nondegraded radioactive components. The concentration and the distribution of radioactivity found in different tissues of six rabbits that received hog renin and six that received rabbit renin showed enormous variation, for which there is no reasonable explanation. A very significant amount of radioactivity was found to be incorporated into a high molecular weight or insoluble form that may be antigen M. A major portion of the radioactivity has a molecular weight of about 40,000 and has been assumed to be unaltered 125I renin. In plasma there was a very high molecular weight radioactive component that was capable of binding to antirenin or antiantigen M antibodies to a limited degree. In addition there was a major component with a molecular weight of 68,000 that is not formed in vitro but is produced in vivo. It resembles prorenin in human plasma in that it does not adsorb on pepstatin-Sepharose and does adsorb on Cibacron Blue. However, it differs from prorenin in that it does not bind to antirenin antibodies nor can it be activated by trypsin.
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PMID:Incorporation of labeled renin into the tissues of the rabbit. 267 72


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