Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.23.15 (renin)
 35,795 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Methods are described for estimating the half-life of angiotensin analogues and renin in the rat, from the time course of the blood pressure changes they evoke. 2. The following half-life values were measured: angiotensin II, 16 +/- 1 sec; angiotensin III, 14 +/- 1 sec; angiotensin II-amide, 15 +/- 1 sec; Sar1-Ala8-angiotensin II, 6.4 +/- 0.6 min; renin, 3.0 +/- 0.4 min. The distribution volume of angiotensin was found to be 18 ml./kg body wt. 3. It is inferred that the Asp1 residue does not reduce the rate of angiotensin II catabolism, but that substitution of this residue by sarcosine may inhibit catabolism while substitution by asparagine has no effect. 4. Five experimental criteria were identified which indicate that these methods give reliable estimates of the half-life. It is suggested that these results are more accurate than most previous half-life estimates. 5 When tachyphylaxis to angiotensin II-amide occurs, the pressor activity of the plasma is not reduced.
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PMID:The half-lives of angiotensin II, angiotensin II-amide, angiotensin III, Sar1-Ala8-angiotensin II and renin in the circulatory system of the rat. 67 33

A four-step method for the purification of human angiotensinogen has been devised. The four steps are: (1) removal of albumin by affinity chromatography on blue dextran-Sepharose, (2) chromatography on DEAE-Sephadex, (3) chromatography on hydroxylapatite, and (4) chromatography on DEAE-cellulose. This method is capable of producing 8 mg of purified angiotensinogen from 150 ml of plasma with 33% overall recovery of renin-releasable angiotensin I. The angiotensinogen appears homogeneous by immunochemical and ultracentrifugal techniques. The N-terminal amino acids have been determined to be alanine and aspartic acid or asparagine.
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PMID:Purification of human angiotensinogen. 90 67

It has been recently reported that, in Xenopus oocytes injected with the mRNA for human renin, this secretory renal glycoprotein acquires phosphomannosyl residues on its asparagine-linked oligosaccharide chains, remains intracellular and undergoes a proteolytic cleavage which removes the prosegment. To understand the influence of glycosylation on the fate of renin in Xenopus oocytes and whether it is specific for human renin, we have expressed human renin and mouse Ren1 renin, which are glycosylated at two and three selected asparagine residues, respectively, and mouse Ren2 renin, which is not glycosylated, in Xenopus oocytes. The majority of human and Ren1 renins remained intracellular and underwent proteolytic cleavage, whereas mouse Ren2 renin was secreted efficiently. When human and Ren1 renins were expressed in oocytes treated with tunicamycin, both were secreted efficiently. A mutant of human renin, which had amino-acid substitutions at both glycosylation sites, was also secreted efficiently, whereas that mutated at one of the two sites was not. These results indicate that the majority of all of the glycosylated renin molecules remain intracellular and undergo proteolytic cleavage, probably due to the acquisition of phosphomannosyl residues, and the human renin remains intracellular if it is only glycosylated at one of the two sites.
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PMID:The influence of glycosylation on the fate of renin expressed in Xenopus oocytes. 211 66

One or both of two putative N-glycosylation sites (at asparagine-5 and -75) of human renin was eliminated by amino acid replacement of the asparagine residue with an alanine residue using site-directed mutagenesis. The three glycosylation-deficient renins (Asn-5, Asn-75, Asn-5 and -75 mutants) were expressed in COS cells and secreted into the conditioned media. The secreted amounts of the three mutants were different from one another, although the mutant and wild-type renins had practically the same specific activity. An Asn-5 and -75 mutant which did not contain any glycosylation sites was unstable in the medium, suggesting that the N-linked oligosaccharides play an important role in stabilization of human renin.
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PMID:Role of N-linked oligosaccharides attached to human renin expressed in COS cells. 328 3

Some of the essential structural requirements for the enzymatic reaction of pure human renin acting on pure human and rat angiotensinogen and on their synthetic tetradecapeptide substrates were investigated. The five carboxy terminal amino acids of synthetic tetradecapeptides played a significant role in substrate recognition and/or hydrolysis by human renin. Kinetic constants Km, Kcat and kcat/Km of the various human renin assays were different according to the substrate used. The presence of either an asparagine or a threonine residue in the S'4 renin subsite did not affect significantly the kinetic constant values. A tyrosine residue, rather than a histidine residue, in the S'3 renin subsite gave the best synthetic substrate studied. When tyrosine residue was present in the S'2 renin subsite an important decrease in kcat was observed. Human angiotensinogen was hydrolysed by human renin with lower Km and kcat values than those measured with human and porcine synthetic substrates, suggesting that the 3-dimensional structure of human angiotensinogen plays a key role in the hydrolysis. This finding was supported by assays performed with rat angiotensinogen, which was cleared by human renin with the same kcat value as rat tetradecapeptide, but with a 49-fold lower Km. Between human and rat angiotensinogen a kcat/Km value of only 2-fold higher has been found in the renin assay using human substrate.
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PMID:Comparative enzymatic studies of human renin acting on pure natural or synthetic substrates. 355 21

A three-dimensional model of human renin has been constructed based on the assumption that the overall folding of the aspartyl proteases is very similar. As a reference, we used penicillopepsin, the structure of which has been reported at a resolution of 1.8 A, and its main chain was traced to build a model of renin. The resulting structure seems to be stable from the hydrophobic and hydrophilic viewpoints. Comparison of the tertiary structure of human renin with that of penicillopepsin and mouse renin suggests the existence of a high structural homology as well as differences in the molecular geometry of the active sites that may influence the substrate specificity. The asparagine side chains in the glycosidation signal of Asn-X-Thr are exposed on the surface. Moreover, the site in human renin that corresponds to the proteolytic cleavage site in mouse renin also appears to be exposed on the surface so as to be easily scissored during the maturation process. The insertions and deletions of amino acid residues were found to arise on the surface, and in some places they occurred in complementary manners. Models of molecular complexes between human renin and renin inhibitor were constructed to understand the interacting modes that indicate how new renin inhibitors develop. Inhibitor-binding sites were directly assigned based on the models of the inhibitor-enzyme complex.
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PMID:Three-dimensional structure of human renin. 388 99

The amino acid sequence of porcine spleen cathepsin D heavy chain has been determined and, hence, the complete structure of this enzyme is now known. The sequence of heavy chain was constructed by aligning the structures of peptides generated by cyanogen bromide, trypsin, and endo-proteinase Lys C cleavages. The structure of the light chain has been published previously. The cathepsin D molecule contains 339 amino acid residues in two polypeptide chains: a 97-residue light chain and a 242-residue heavy chain, with a combined Mr of 36,779 (without carbohydrate). There are two carbohydrate units linked to asparagine residues 70 and 192. The disulfide bond arrangement in cathepsin D is probably similar to that of pepsin, because the positions of six half-cystine residues are conserved. The active site aspartyl residues, corresponding to aspartic acid-32 and -215 of pepsin, are located at residues 33 and 224 in the cathepsin D molecule. The amino acid sequence around these aspartyl residues is strongly conserved. Cathepsin D shows a strong homology with other acid proteases. When the sequence of cathepsin D, renin, and pepsin are aligned, 32.7% of the residues are identical. The homology is observed throughout the length of the molecules, indicating that three-dimensional structures of all three molecules are similar.
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PMID:Amino acid sequence of porcine spleen cathepsin D. 658 85

Angiotensinogen precursors synthesized by rabbit reticulocyte lysate primed with rat liver RNA were compared with angiotensinogen secreted by rat hepatoma cells and rat hepatocytes using immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Inhibition of glycosylation with tunicamycin permitted identification of the nonglycosylated form of secreted angiotensinogen. Whereas angiotensinogen secreted by hepatoma cells and hepatocytes showed electrophoretic heterogeneity (mol wt, 52-62 X 10(3], tunicamycin-treated cells secreted only a single angiotensinogen species [mol wt, 48.3 +/- 0.7 X 10(3) (mean +/- SD)], which could be cleaved by renin. Two putative angiotensinogen precursors were synthesized in the reticulocyte lysate: a major protein of 52.5 +/- 1.0 X 10(3) mol wt and a minor protein of 55.7 +/- 1.3 X 10(3) mol wt. Evidence that these proteins represent separate angiotensinogen precursors includes the following. 1) Both proteins were recognized by five different polyclonal antibodies and two monoclonal antibodies. 2) Both proteins increased in parallel in reticulocyte lysates primed with liver RNA from rats nephrectomized and given hormones that increase liver angiotensinogen production. 3) Both proteins were cleaved by renin to produce a single protein of 47.6 +/- 0.8 X 10(3) mol wt. 4) The des-angiotensin I-angiotensinogen generated by renin treatment of the lysate had an electrophoretic mobility identical to that of des-AI-angiotensinogen produced by renin treatment of nonglycosylated angiotensinogen secreted by tunicamycin-treated hepatoma cells and hepatocytes. These studies suggest that rat liver synthesizes two separate angiotensinogen precursors which may differ only in the size of their prepro sequence. The heterogeneity of secreted angiotensinogen can be fully accounted for by differences in N-glycosylation of asparagine residues of the molecule. Glycosylation of angiotensinogen is not essential for its synthesis, processing, and secretion or its hydrolysis by renin.
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PMID:Characterization of precursor and secreted forms of rat angiotensinogen. 669 62

Following addition of N-iodosuccinimide to glycals, reductive hydrogenolysis and ring opening gave 2-deoxy-alpha-N-glycopeptides carrying a deaminated asparagine unit. This reaction could be performed employing glucal, galactal, L-rhamnal, L-fucal and lactal to give the corresponding glycoconjugate building blocks 11, 12, 17, 22, 27 and 32. Further NIS-mediated glycosylation of the rhamno derivative 21 led to simple trisaccharide peptide adducts 45. Peptide synthesis of the gluco building unit with different preassembled oligopeptides afforded glycoconjugates 36, 39, 41 and 42 assumed to be of interest as potential inhibitors of the renin-angiotensin system.
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PMID:Synthesis and structural studies of asparagine-modified 2-deoxy-alpha-N-glycopeptides associated with the renin-angiotensin system. 775 24

Among the limitations to the practical therapeutic oligopeptide are low oral availability, indifferent aqueous solubility, and an astonishing efficient sequestration and biliary elimination by a multi-capacity liver transporter. Given the purposed use of N- and O- linked saccharides as functional appendages of eukaryotic peptides and proteins, a strategy of glycopeptide mimicry was examined for the oligopeptide renin inhibitor, ditekiren. The anticipation was that the saccharide would impart significant aqueous solubility, and might impact beneficially on the remaining two limitations. Execution of this approach was achieved by the removal of the (dimethylethoxy)carbonyl amino terminus of ditekiren, and its substitution by Boc-L-asparagine N-linked mono- and disaccharides. Potent hypotensive activity, as measured by a human renin-infused rat assay, is observed for virtually all of these structures (N-linked beta-pyranose D-N-acetyglucosaminyl, D-glucosaminyl, D-N-acetylgalactosaminyl, D-mannosyl, D-galactosyl, D-maltosyl, D-cellobiosyl, D-chitobiosyl, but not L-fucosyl). The basis for this dramatic improvement (relative to ditekiren in the same assay) is the diversion of the peptide clearance from rapid liver biliary clearance to slower urinary clearance (Fisher, J. F.; Harrison, A. W.; Wilkinson, K. F.; Rush, B. R.; Ruwart, M. J. J. Med. Chem. 1991, 34, 3140). Guided by the human renin-infused rat hypertension assay, an evaluation of the linker-saccharide pairing was made. Loss of hypotensive activity is observed upon substitution of the Boc-L-asn by Boc-D-asn, and by removal of the Boc amino terminus of the glycopeptide. Potent hypotensive activity is preserved by replacement of the Boc-L-asn linker by succinate, malate, tartrate, and adipate linkers. With the longer adipate spacer, attachment of the saccharide to the P-3 phenylalanine--with omission of the P-4 proline--retains activity. These data suggest value to the glycopeptide guise for preserving the in vivo activity, and for the beneficial manipulation of pharmacodynamics, of this renin inhibitory oligopeptide. This strategy may have general applicability.
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PMID:Appraisal of a glycopeptide cloaking strategy for a therapeutic oligopeptide: glycopeptide analogs of the renin inhibitor ditekiren. 778 97


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