| 6330563 |
Human epidermal growth factor receptor cDNA is homologous to a variety of RNAs overproduced in A431 carcinoma cells. |
10.1038/309806a0 |
Nature |
Human epidermal growth factor receptor cDNA is homologous to a variety of RNAs overproduced in A431 carcinoma cells.
Abstract
- The recently discovered similarity between the human epidermal growth factor (EGF) receptor and the avian erythroblastosis virus v-erb-B protein supports the hypothesis that viral oncogenes share a common evolutionary origin with genes encoding growth-regulating cell-surface receptors. To elucidate the relationship between receptors and malignant transformation, we have now used a fragment of v-erb-B as a probe to screen a cDNA library of mRNA from A431 human carcinoma cells, which possess a large number of EGF receptors. Of the six clones isolated, the largest (pE7) contains an insert of 2.4 kilobase pairs (kbp) whose deduced amino acid sequence is homologous to the v-erb-B protein and identical to reported EGF receptor peptide sequences. This pE7 cDNA hybridized to three prominent RNAs of approximately 10, 5.6 and 2.9 kilobases (kb), and to three minor species of 6.3, 4.6 and 3.3 kb. All were present in elevated levels in A431 cells. The prominent 2.9-kb RNA was homologous only to the 5' portion of the pE7 insert. This result raises the possibility that differential RNA processing is used by A431 cells to generate a variety of RNAs.
|
| 6337880 |
Mode of action of bottromycin A2: effect of bottromycin A2 on polysomes |
10.1016/0014-5793(83)80118-5. |
FEBS Lett |
Mode of action of bottromycin A2: effect of bottromycin A2 on polysomes
Abstract
- When bottromycin A2 was added to an in vitro protein synthesis system carried out by naturally occurring polysomes, it inhibited protein synthesis effectively. Examination of the 3 steps of peptide chain elongation revealed that the binding of aminoacyl-tRNA to the polyribosomes was inhibited by bottromycin A2. In contrast, we concluded that the peptide bond formation and the translocation steps in this system were not inhibited by bottromycin A2 on the basis of the following observations: (1) The break-down of polysomes, which is dependent on EFG, puromycin and RR (ribosome releasing) factor, was insensitive to bottromycin A2; (2) The puromycin dependent release of polypeptide from polysomes, with or without EFG, was not inhibited by bottromycin A2. Thus bottromycin specifically interferes with proper functioning of the A sites of polysomes. This is consistent with the results obtained using the model system with synthetic polynucleotides.
|
| 6384168 |
Studies on the selectivity of action of colistin, colistin nonapeptide and colistin heptapeptide on the cell envelope of Escherichia coli |
10.7164/antibiotics.37.926. |
J Antibiot (Tokyo) |
Studies on the selectivity of action of colistin, colistin nonapeptide and colistin heptapeptide on the cell envelope of Escherichia coli
Abstract
|
| 6405779 |
Determination of the amino acid substitution in human prothrombin type 3 (157 Glu leads to Lys) and the localization of a third thrombin cleavage site |
10.1111/j.1365-2141.1983.tb02092.x. |
Br J Haematol |
Determination of the amino acid substitution in human prothrombin type 3 (157 Glu leads to Lys) and the localization of a third thrombin cleavage site
Abstract
- Prothrombin was purified from normal blood donors and individuals heterozygous for prothrombin type 3. Comparison of the purified prothrombin preparations by tryptic peptide mapping, amino acid analysis and automated sequencing after thrombin digestion, has indicated that prothrombin type 3 results from the substitution of a lysine residue for glutamic acid at position 157. This substitution can result from a single base change in the structural gene and explains the relatively slow electrophoretic mobility of prothrombin type 3 at alkaline pH. An additional thrombin cleavage site in profragment 1 has been identified at arginine 54 by automated sequence analysis of thrombin digests by prothrombin.
|
| 6414364 |
Polycations sensitize enteric bacteria to antibiotics |
10.1128/AAC.24.1.107. |
Antimicrob Agents Chemother |
Polycations sensitize enteric bacteria to antibiotics
Abstract
- Polymyxin B nonapeptide, a polymyxin B derivative which lacks the fatty acyl part and the bactericidal activity of polymyxin, was shown to sensitize smooth encapsulated Escherichia coli (O18:K1) and smooth Salmonella typhimurium to hydrophobic antibiotics (novobiocin, fusidic acid, erythromycin, clindamycin, nafcillin, and cloxacillin). The polymyxin B nonapeptide-treated bacteria were as sensitive to these antibiotics as are deep rough mutants. A lysine polymer with 20 lysine residues (lysine 20) had a largely similar effect. Larger lysine polymers and the protamine salmine were bactericidal but, at sublethal concentrations, sensitized the strains to the antibiotics mentioned above, whereas lysine4, streptomycin, cytochrome c, lysozyme, and the polyamines cadaverine, spermidine, and spermine had neither bactericidal nor sensitizing activity.
|
| 6424102 |
Actions of intracerebroventricular administration of kyotorphin and an analog on thermoregulation in the mouse |
10.1016/0196-9781(83)90081-5. |
Peptides |
Actions of intracerebroventricular administration of kyotorphin and an analog on thermoregulation in the mouse
Abstract
- Intracerebroventricular (ICV) administration of kyotorphin (L-Tyr-L-Arg) and cyclo (N-methyl-L-Tyr-L-Arg), its analog, produced significant dose-dependent hypothermic responses in mice at an ambient temperature of 24 degrees C. The hypothermic action of kyotorphin was much greater than that of Met-enkephalin (Met-ENK) but less than that of cyclo NMTA. This action was slightly but not significantly reversed by intraperitoneally administered naloxone (8 mg/kg), an opioid receptor antagonist. Met-ENK utilized as a control peptide in this study also produced a dose-dependent hypothermia which was slightly antagonized by naloxone (8 mg/kg, IP). Thyrotropin releasing hormone (TRH) injected ICV produced hyperthermia dose-dependently. The hypothermia induced by kyotorphin, its cyclic analog and Met-ENK was prevented by a small dose of TRH (0.18 microgram = 0.5 nmol/animal) which by itself had little effect on body temperature. A TRH neuronal system in the brain may explain the mechanism of kyotorphin-induced hypothermia. However, there was little evidence of involvement of opioid receptors. The present study demonstrates a potent action of kyotorphin and its analog on thermoregulation.
|
| 6441791 |
Structures of bacillomycin D and bacillomycin L peptidolipid antibiotics from Bacillus subtilis |
10.7164/antibiotics.37.1600. |
J Antibiot (Tokyo) |
Structures of bacillomycin D and bacillomycin L peptidolipid antibiotics from Bacillus subtilis
Abstract
- The complete structures of bacillomycin D and bacillomycin L were revised by FAB mass spectrometry and by Edman degradation of the derivatives resulting from the N-bromosuccinimide reaction. The homologous components of both series of antibiotics were separated by HPLC and the beta-amino acids were identified by capillary gas chromatography.
|
| 6492076 |
Covalent binding of isomeric 7-(2,3-epoxypropoxy)actinomycin D to DNA |
10.1021/jm00377a015. |
J Med Chem |
Covalent binding of isomeric 7-(2,3-epoxypropoxy)actinomycin D to DNA
Abstract
- We have examined the ability of 7-(2,3-epoxypropoxy)actinomycin D (EPA) to bind covalently to DNA and to 2'-deoxyribonucleoside 5'-monophosphates in a simple system in vitro. We have observed initially that EPA binds to DNA and deoxymono- and deoxydinucleotides with intercalative or stacking interactions that are characteristic of actinomycin D (AMD). When EPA is incubated (37 degrees C) for a prolonged period (pH 7.4, 6 h) in contact with either DNA or deoxyribonucleotides, it forms covalent adducts. Deoxyguanosine is always the preferred site of reaction by EPA. After enzymatic digestion of EPA-DNA adduct, three deoxyguanosine (EPA-dG) adducts, one major and two minor, were isolated. These adducts are separable from one another and from other deoxyribonucleoside adducts, e.g., EPA-dA and EPA-dC by reverse-phase HPLC. The authentic EPA-dG, EPA-dA, and EPA-dC adducts were synthesized by a chemical reaction of the epoxide in EPA with the deoxyribonucleotides followed by enzymatic dephosphorylation of the products. From the EPA-DNA adduct the EPA-dG adducts accounted for congruent to 2.2% of EPA employed; the remainder of EPA was completely hydrolyzed to an epoxide ring opened diol derivative, DHPA. DHPA binds to DNA by intercalation only and it does not form covalent adducts. Another model analogue of EPA (EPAMDEA) has the same epoxide-substituted chromophore but lacks the peptide lactone functions; it fails to associate with DNA and consequently it shows no covalent binding of its epoxide with DNA. Formation of a noncovalent intercalation complex between EPA and DNA appears to be a prerequisite for the covalent reaction. Presumably because of these dual interactions, EPA demonstrates superior antitumor activities both in human leukemic cells (CCRF-CEM) in vitro and P388 and L1210 cells in mice. The DNA base specific alkylating activity of EPA, which is derived from a combination of the actinomycin D (AMD) structure and the new epoxide function in the molecule of EPA, attributes to EPA a potentially novel pharmacological behavior that is not inherent of AMD."
|
| 6501109 |
Empedopeptin (BMY-28117), a new depsipeptide antibiotic. II. Structure determination |
10.7164/antibiotics.37.958. |
J Antibiot (Tokyo) |
Empedopeptin (BMY-28117), a new depsipeptide antibiotic. II. Structure determination
Abstract
- Structure of a new antibiotic, empedopeptin, has been determined. It is a cyclic depsipeptide composed of two mol of D-serine and one mol each of beta-hydroxytetradecanoic acid, L-arginine, D- and L-proline, L-3-hydroxyproline and D- and L-beta-hydroxyaspartic acid. The sequence of these moieties was established by partial hydrolysis and mass spectral analysis of the antibiotic.
|
| 6505082 |
Studies on antitumour cyclic hexapeptides RA obtained from Rubiae radix, Rubiaceae (IV): Quantitative determination of RA-VII and RA-V in commercial Rubiae radix and collected plants |
10.1055/s-2007-969718. |
Planta Med |
Studies on antitumour cyclic hexapeptides RA obtained from Rubiae radix, Rubiaceae (IV): Quantitative determination of RA-VII and RA-V in commercial Rubiae radix and collected plants
Abstract
|
| 6510638 |
Cell growth-inhibitory effects of derivatives of antitumor cyclic hexapeptide RA-V obtained from Rubiae radix (V) |
None |
Gan |
Cell growth-inhibitory effects of derivatives of antitumor cyclic hexapeptide RA-V obtained from Rubiae radix (V)
Abstract
- Alkylehter and ester derivatives of the antitumor cyclic hexapeptide RA-V obtained from the roots of Rubia cordifolia (Rubiaceae) were synthesized and bioassayed for activity against cultured tumor cells. RA-V and its n-hexylether showed significant effects against human nasopharynx carcinoma (KB), P388 lymphocytic leukemia and MM2 mammary carcinoma cells. The activity values (log 1/IC50) of ether derivatives of RA-V gave an upward parabolic or bilinear relationship when plotted against log P (P: partition coefficient determined with the 1-octanol/water system) as the carbon number of the side chain at the phenol moiety of RA-V was increased, the optimum log P values being in the range from 3.5 to 4.9. The ester derivatives showed a similar relationship, the optimum log P values being 6.3-6.7, which is higher than that of the ether derivatives. The lethal effect of RA-V on KB cells was clearly different from that of mitomycin C, and RA-V was concluded to be a "time-dependent drug" like vinblastine.
|
| 6546714 |
Prevention of stress decrease in natural killer activity by sodium oxybutyrate and the delta-sleep peptide |
None |
Dokl Akad Nauk SSSR |
Prevention of stress decrease in natural killer activity by sodium oxybutyrate and the delta-sleep peptide
Abstract
|
| 6547407 |
Cyclic peptides. XVI. Syntheses of AM-toxin I analogs containing a lower or higher homolog of the component L-2-amino-5-(p-methoxyphenyl)pentanoic acid residue |
None |
Int J Pept Protein Res |
Cyclic peptides. XVI. Syntheses of AM-toxin I analogs containing a lower or higher homolog of the component L-2-amino-5-(p-methoxyphenyl)pentanoic acid residue
Abstract
- In order to investigate the influence of the side-chain length at position 3 of AM-toxin I (cyclic tetradepsipeptide) on necrotic activity for apple leaf, two analogs of AM-toxin I, L-2-amino-4-(p-methoxyphenyl)butanoic acid-AM-toxin I and L-2-amino-6-(p-methoxyphenyl)hexanoic acid-AM-toxin I, were synthesized by the conventional method. Spectra of 1H-n.m.r., u.v. and CD of the analogs were similar to those of natural or synthetic AM-toxin I. The toxic activities of the analogs for apple leaf, however, were weak, indicating that the exact side-chain length at position 3 must be one of the important factors for the induction of the activity. The interaction between AM-toxin I and a possible receptor on apple leaf is discussed.
|
| 6547408 |
Antidiuretic and pressor activities of vasopressin analogs with L-alaninamide and D-alaninamide substitutions at position 9 |
10.1111/j.1399-3011.1984.tb02757.x. |
Int J Pept Protein Res |
Antidiuretic and pressor activities of vasopressin analogs with L-alaninamide and D-alaninamide substitutions at position 9
Abstract
- Analogs of arginine vasopressin (AVP) and lysine vasopressin (LVP)--with an L-alaninamide residue or a D-alaninamide residue replacing the naturally occurring glycinamide in position 9--lose virtually all pressor activity but retain from 10 to 70% of the antidiuretic activity of their parent hormones. These findings, in conjunction with the data of others on the biological consequences of alterations in positions 7 and 8, show that the antidiuretic receptor will tolerate considerably more structural alteration in the C-terminal tripeptide "tail" of the vasopressins than will the pressor receptor.
|
| 6548738 |
BMY-28160, a new peptide antibiotic |
10.7164/antibiotics.37.1257. |
J Antibiot (Tokyo) |
BMY-28160, a new peptide antibiotic
Abstract
|
