| 6152349 |
The mechanism of degradation of cyclo(-Asn-Phe-Phe-D-Trp-Lys-Thr-Phe-Gaba-) and the relative stabilities of this and other octapeptide somatostatin analogues in rat intestinal juice |
10.1016/0167-0115(84)90050-8. |
Regul Pept |
The mechanism of degradation of cyclo(-Asn-Phe-Phe-D-Trp-Lys-Thr-Phe-Gaba-) and the relative stabilities of this and other octapeptide somatostatin analogues in rat intestinal juice
Abstract
- The mechanism of degradation of the somatostatin analogue cyclo(-Asn-Phe-4-3H-Phe-D-Trp-Lys-Thr-Phe-Gaba-) in rat intestinal juice in vitro has been studied by isolation and identification of cleavage products. The analogue is much more stable than somatostatin but is nevertheless degraded in minutes in dilute intestinal juice. There is a single primary cleavage site at Lys-Thr and the linear peptide thus formed is subsequently rapidly degraded to smaller peptides. Analogues with a modified lysine are markedly stabilised relative to the octapeptide analogue.
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| 6156806 |
Energy transfer and binding competition between dyes used to enhance staining differentiation in metaphase chromosomes |
10.1007/BF00328469. |
Chromosoma |
Energy transfer and binding competition between dyes used to enhance staining differentiation in metaphase chromosomes
Abstract
- The ability of electronic energy transfer and direct binding competition between pairs of dyes to enhance contrast in human or bovine metaphase chromosome staining patterns is illustrated, and the relative effectiveness of these two mechanism compared. The existence of energy transfer between quinacrine or 33258 Hoechst and 7-amino-actinomycin D in doubly stained chromosomes is demonstrated directly by microfluorometry. The ability of the dyes 7-amino-actinomycin D, methyl green, or netropsin, acting as counterstains, to displace quinacrine, 33258 Hoechst, or chromomycin A3 from chromosomes, is estimated by quantitative analysis of energy transfer data, by photobleaching of the counterstains, or by selective removal of counterstains by appropriate synthetic polynucleotides. Effects on the fluorescence of soluble 33258 Hoechst-DNA complexes due to energy transfer or binding displacement, by actinomycin D or netropsin, respectively, are further differentiated by nanosecond fluorescence decay measurements. Examples are presented of dye combinations for which (a) energy transfer is the primary mechanism operative, (b) binding competition exists, with consequences reinforcing those due to energy transfer, or (c) binding competition is the most important interaction. These analyses of mechanisms responsible for contrast enhancement in doubly stained chromosomes are used to derive information about the relationship between chromosome composition and banding patterns.
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| 6161852 |
Chemical syntheses of biologically active cyclic peptides in the light of known biosynthetic pathways |
10.1042/bst0080748. |
Biochem Soc Trans |
Chemical syntheses of biologically active cyclic peptides in the light of known biosynthetic pathways
Abstract
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| 6165619 |
Primary structure of the 'bait' region for proteinases in alpha 2- macroglobulin. Nature of the complex. |
10.1016/0014-5793(81)80197-4 |
FEBS Lett. |
Primary structure of the 'bait' region for proteinases in alpha 2- macroglobulin. Nature of the complex.
Abstract
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| 6167263 |
Proteolytic cleavage sites on alpha 2-macroglobulin resulting in proteinase binding are different for trypsin and Staphylococcus aureus V-8 proteinase. |
10.1016/s0006-291x(81)80055-1 |
Biochem. Biophys. Res. Commun. |
Proteolytic cleavage sites on alpha 2-macroglobulin resulting in proteinase binding are different for trypsin and Staphylococcus aureus V-8 proteinase.
Abstract
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| 6172288 |
Primary and secondary cleavage sites in the bait region of alpha 2- macroglobulin. |
10.1016/0014-5793(81)80804-6 |
FEBS Lett. |
Primary and secondary cleavage sites in the bait region of alpha 2- macroglobulin.
Abstract
|
| 6173016 |
Activity of di-beta-lysyl-capreomycin IIA and palmitoyl tuberactinamine N against drug-resistant mutants with altered ribosomes |
10.1128/AAC.20.6.834. |
Antimicrob Agents Chemother |
Activity of di-beta-lysyl-capreomycin IIA and palmitoyl tuberactinamine N against drug-resistant mutants with altered ribosomes
Abstract
- The effects of 61 synthetic tuberactinomycin derivatives on polypeptide synthesis were tested in bacterial cell-free systems. Di-beta-lys-capreomycin IIA was more effective than the natural product. Palmitoyl tuberactinamine N inhibited the growth of tuberactinomycin-resistant mutants and was not a ribosome inhibitor.
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| 6179914 |
Chemical and biological properties of formyl gramicidins S |
10.7164/antibiotics.35.571. |
J Antibiot (Tokyo) |
Chemical and biological properties of formyl gramicidins S
Abstract
- The mono- and diformyl gramicidins S have been prepared. Monoformyl gramicidin S retains about 50% of the expected biological activity and the diformyl derivative is inactive. It is therefore, conceivable that both the amino groups equally contribute to the biological activity of the antibiotic. However, monoformyl gramicidin S has been found to form aggregate and this aggregate is more stable under acidic conditions rather than in neutral or alkaline solutions. Denaturing agent urea has been found useful in dissociating the aggregate. The aggregating ability of formyl peptides is at least be due to their formyl groups.
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| 6184702 |
A fragment of substance P with specific central activity: SP(1-7) |
10.1016/0196-9781(82)90027-4. |
Peptides |
A fragment of substance P with specific central activity: SP(1-7)
Abstract
- Amino-terminal fragments of substance P (SP), SP(1-7) and SP(1-8), were found to produce naloxone-reversible antinociception in the mouse similar to that produced by SP. Similar to SP, these peptides produce antinociception only within a narrow dose range. They have no activity on smooth muscle or blood pressure. These results suggest that contrary to peripheral effects of SP, which are mediated by receptors which recognize the carboxy-terminal part of the SP molecule, certain central actions of SP are mediated by receptors which recognize the amino-terminal part of the SP molecule. SP may be metabolized to this active fragment prior to its action at these receptors.
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| 6188846 |
Circular and circularly permuted forms of bovine pancreatic trypsin inhibitor |
10.1016/s0022-2836(83)80265-4. |
J Mol Biol |
Circular and circularly permuted forms of bovine pancreatic trypsin inhibitor
Abstract
- Two novel forms of bovine pancreatic trypsin inhibitor have been prepared. The amino- and carboxyl-termini, which are in close proximity in the native conformation, were linked together in a peptide bond, thus generating a molecule with a circular backbone. The circular molecule was then cleaved between Lys15 and Ala16, to yield a linear molecule whose sequence is a circular permutation of that of bovine pancreatic trypsin inhibitor. Both of these modified forms could refold to the native conformation after being reduced, and promise to be interesting subjects for further folding experiments.
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| 6193012 |
4,4'-D-diaminopropionic acidgramicidin S: a synthetic gramicidin S analog with antimicrobial activity against Gram-negative bacteria |
10.1016/0014-5793(83)80736-4. |
FEBS Lett |
4,4'-D-diaminopropionic acidgramicidin S: a synthetic gramicidin S analog with antimicrobial activity against Gram-negative bacteria
Abstract
- Gramicidin S is especially active against Gram-positive bacteria; e.g., Staphylococcus aureus. An analog, 4,4'-D-diaminopropionic acidgramicidin S, which contains D-diaminopropionic acid residues instead of D-phenylalanine residues, has been synthesized. This analog is active against some of the Gram-negative bacteria; e.g., Escherichia coli and Salmonella typhosa. Activities of several related analogs are discussed."
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| 6195065 |
Human neutrophil elastase and cathepsin G cleavage sites in the bait region of alpha 2-macroglobulin. Proposed structural limits of the bait region. |
10.1515/bchm2.1983.364.2.1297 |
Hoppe-Seyler's Z. Physiol. Chem. |
Human neutrophil elastase and cathepsin G cleavage sites in the bait region of alpha 2-macroglobulin. Proposed structural limits of the bait region.
Abstract
- The sites of cleavage in the "bait region" of human alpha 2-macroglobulin made by both neutrophil elastase and cathepsin G, as the first step in their inactivation by this inhibitor, have been identified. These positions are at a valylhistidyl bond for elastase and a phenylalanyl-tyrosyl bond for cathepsin G. All of the proteinases tested so far, including those utilized in this study, are cleaving within a twenty-seven aminoacid peptide sequence occurring between two proline residues. It is suggested that this area represents the outer limits of the "bait region" loop.
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| 6198315 |
Antibacterial activity of palmitoyltuberactinamine N and di-beta-lysylcapreomycin IIA |
10.7164/antibiotics.36.1729. |
J Antibiot (Tokyo) |
Antibacterial activity of palmitoyltuberactinamine N and di-beta-lysylcapreomycin IIA
Abstract
- Palmitoyltuberactinamine N (Pal-Tua N) and di-beta-lysylcapreomycin IIA (di-beta-Lys-Cpm IIA), which are synthetic derivatives of the antituberculous agent tuberactinomycin (Tum) and capreomycin (Cpm) respectively, were tested for anti-bacterial activity. Pal-Tua N inhibited not only tuberactinomycin-resistant Mycobacterium smegmatis but also Escherichia coli, Corynebacterium diphtheriae, Staphylococcus aureus, Streptococcus pyogenes, although it has lost activity against Mycobacterium tuberculosis. Di-beta-Lys-Cpm IIA inhibited the growth of laboratory-derived Tum-resistant M. smegmatis and M. tuberculosis as well as Tum-resistant M. tuberculosis from patients with one exceptional case.
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| 6203908 |
Primary structure of human alpha 2-macroglobulin. V. The complete structure. |
10.1016/s0021-9258(17)39730-2 |
J. Biol. Chem. |
Primary structure of human alpha 2-macroglobulin. V. The complete structure.
Abstract
- The primary structure of the tetrameric plasma glycoprotein human alpha 2-macroglobulin has been determined. The identical subunits contain 1451 amino acid residues. Glucosamine-based oligosaccharide groups are attached to asparagine residues 32, 47, 224, 373, 387, 846, 968, and 1401. Eleven intrachain disulfide bridges have been placed (Cys25-Cys63, Cys228-Cys276, Cys246-Cys264, Cys255-Cys408, Cys572-Cys748, Cys619-Cys666, Cys798-Cys826, Cys824-Cys860, Cys898-Cys1298, Cys1056-Cys1104, and Cys1329-Cys1444). Cys-447 probably forms an interchain bridge with Cys-447 from another subunit. The beta-SH group of Cys-949 is thiol esterified to the gamma-carbonyl group of Glx-952, thus forming an activatable reactive site which can mediate covalent binding of nucleophiles. A putative transglutaminase cross-linking site is constituted by Gln-670 and Gln-671. The primary sites of proteolytic cleavage in the activation cleavage area (the "bait" region) are located in the sequence: -Arg681-Val-Gly-Phe-Tyr-Glu-. The molecular weight of the unmodified alpha 2-macroglobulin subunit is 160,837 and approximately 179,000, including the carbohydrate groups. The presence of possible internal homologies within the alpha 2-macroglobulin subunit is discussed. A comparison of stretches of sequences from alpha 2-macroglobulin with partial sequence data for complement components C3 and C4 indicates that these proteins are evolutionary related. The properties of alpha 2-macroglobulin are discussed within the context of proteolytically regulated systems with particular reference to the complement components C3 and C4.
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| 6250564 |
Characterization of octapeptin-membrane interactions using spin-labeled octapeptin |
10.1021/bi00555a032. |
Biochemistry |
Characterization of octapeptin-membrane interactions using spin-labeled octapeptin
Abstract
- Octapeptin is a membrane-active peptide antibiotic that contains a C10 fatty acid covalently attached to the peptide through an amide bond. Interactions of octapeptin with bacterial membranes and phospholipids were characterized by using spin-labeling techniques and octapeptin derivatives containing fatty acids of varying chain length. Acyl modification of octapeptin demonstrated that the fatty acid of the antibiotic contributed to the antimicrobial activity of octapeptin and its affinity for membranes. The influence of octapeptin and C2 acyloctapeptin on the rates of ascorbate reduction of several membrane-bound doxyl stearates was also examined. These studies demonstrated that octapeptin increaed the rate of diffusion of ascorbate into the lipid bilayer and suggested that the acyl chain contributed to this activity. In addition, an acyl spin-labeled analogue of octapeptin was prepared and shown to retain biological activity. Spectral analysis showed that octapeptin does not aggregate in solution over a wide concentration range. However, the isotropic splitting constant indicated that the acyl chain of octapeptin is not completely exposed to water. It is proposed that the acyl chain of octapeptin in solution interacts with hydrophobic amino acids in the peptide, which partially shields the acyl chain from water. Spectral features of the spin-labeled antibiotic bound to phospholipid dispersions were consistent with directional binding of octapeptin to lipid bilayers with insertion of the fatty acid into the hydrocarbon domain.
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