摘要:

Acquired immunodeficiency syndrome (AIDS) is initiated by the attachment of the human immunodeficiency virus (HIV) to a surface glycoprotein CD4present on T4helper/inducer lymphocytes, monocytes/macrophages and other cells. A simple octapeptide (H‐Ala‐Ser‐Thr‐Thr‐Thr‐Asn‐Tyr‐Thr‐OH, peptide T) seems to inhibit HIV infectivity and to activate human monocyte chemotaxis. In order to studyin vitrometabolic stability and structure‐activity relationships, peptide T and a number of analogues were prepared and tested on human monocytes by chemotactic assay. Peptide T and the shorter fragments T(3‐8)‐OH and T(4–8)‐OH displayed potent bioactivity (maximal chemotactic activity in the range 10‐11‐10‐10M). TheC‐terminal heptapeptide showed a reduction of potency, while further truncations atN‐terminus of T(4–8)‐OH abolished the biological action. In the octapeptide series, whereas the α‐amino butyric acid (Abu) substitution for Thr4was well tolerated, the same “slight” structural change at Thr5or Thr8was very detrimental. Finally, [d‐Asn6]T(1‐8)‐OH analogue has low chemotactic activity. All these results indicate that i) theC‐terminal pentapeptide is the minimum sequence required for bioactivity, ii) residues 5 to 8 appear to play a crucial biological role, iii) peptide T chemotaxis is mediated, at least in part, through the polar properties of Thr side chains at the critical positions 5 and 8, while the Thr4does not interfere with biological characteristics of peptides. With regard to the enzymic degradation, thein vitroexperiments showed the susceptibility of peptide T to rapid metabolism by human or rat plasma (T1/2 = 5.2 min), rat brain (T1/2 = 2.1 min) and kidney (T1/2 = 0.4 min) enzymes. The main metabolic product appears to be theC‐terminal hepta

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1990.tb00239.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

The model peptide TRH was successfully synthesized using benzotriazol‐l‐yl‐oxy‐tris(dimethylamino)phosphonium hexafluorophosphate (BOP reagent). The coupling reactions were carried out inN,N‐dimethylformamide orN‐methylpyrrolidone. These solvents allowed the incorporation of theN‐terminal pyroglutamic acid residue into the peptide chain, without using the derivative bearing theN‐benzyloxycarbonyl group, which acts as a solubility promoter. A comparative racemization study showed that Boc‐His(Tos) can be coupled by means of BOP reagent with less racemization than with DCC when the amount of diisopropylethylamine (DIEA) is kept minimal (same ratio of equivalents as for Boc‐His(Tos), i.e. 3 equiv.). However, with the use of a larger amount of DIEA in the coupling mixture (9 equiv.), approximately 3% of epimer was found in the crude product. Our study showed that even under low DIEA conditions, the rate of coupling of the residues with BOP remained comparable to tha

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1990.tb00240.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

A novel bifunctional compound, 9‐(hydroxymethyl)‐2‐fluoreneacetic acid, was synthesized, coupled to benzhydrylamine‐resin, and evaluated for its application to the solid phase synthesis of protected peptide fragments. Anchor‐bond cleavage was achieved with 15% pipetidine/DMF. A protected heptapeptide, Boc‐Val‐Val‐Ser(Bzl)‐His(Tos)‐Phe‐Asn‐Lys‐(Z)‐OH, corresponding to the sequence (1–7) of rat‐transforming growth factor‐α, was synthesized using this new su

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1990.tb00241.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

The effects of substituting the enkephalin moiety of dynorphin with the dermorphin sequence were studied on the receptor preference, analgesic, and peripheral opioid potencies by using synthetic dermorphin‐dynorphin hybrid peptides as the probe. Replacement of the enkephalin moiety of dynorphin with the dermorphin or dermorphin1–5sequence caused a remarkable increase in analgesic potency, and a 3‐6 fold increase in potency of binding against [3H]‐dihydromorphine. The potency of receptor binding against [3H]‐EKC was also increased by incorporation of the whole dermorphin sequence into the dynorphin molecule. In the presence of NaCl (100mM), the effect of enhancing binding against [3H]‐EKC due to dermorphin substitution disappeared, suggesting the contribution of opioid μreceptor. Peripheral opioid activities assayed by various smooth muscle preparations showed that dermorphin incorporation caused a decrease in the potency of inhibition of the contractions of the guinea pig ileum and the rabbit vas deferens, no change in potency on the mouse vas deferens, and a marked increase in the inhibition of the rat vas deferens. Among the peripheral opioid activities only that assayed with the rat vas deferens appears to correlate approximately with the analgesic and the receptor binding activities. Judging from the relative potencies obtained from all assays, it is evident that theN‐terminal dermorphin moiety, but not theC‐terminal dynorphin fragment, dominates the opioid activity and receptor preference of th

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1990.tb00242.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

The immunochemical behavior of several fragments of equine growth hormone (eGH) was examined using competitive binding assays with antibodies (Abs) to eGH obtained from different sources. Antigenicity was detected within the sequences 5–72 and 73–123 by rabbit Abs to eGH and by three mouse monoclonal antibodies (MAbs) produced by using bovine growth hormone as immunogen, but showing heteroclitic properties towards eGH. The polyclonal Abs to eGH also recognized as immunoreactive two smaller peptides corresponding to the amino acid residues 52–72 and 110–123. By contrast, the heteroclitic Abs to eGH developed by hypopituitary patients therapeutically injected with human growth hormone failed to react with any eGH‐derived fragment. The rabbit polyclonal Abs and the mouse MAbs scarcely discriminated between native and S‐carbamidomethylated eGH, while the heteroclitic human Abs detected a clear difference between the native and the modif

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1990.tb00243.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Previous molecular mechanics calculations on the effect of Ca(II) and Mg(II) ions on the conformation of the 18‐23 loop of bovine prothrombin [Maynardet al.1988,Int. J. Peptide Protein Res.31, 137–1491 are extended to include the effect of a model phospholipid head group methyl[l‐seryl] phosphate. Whereas the conformation of the Gla‐21 Pro‐22 amide bond remains decidedlytransin the absence of the model head group, in its presence, thecisCa(II) ion induced (but not Mg(II)) form is significantly lowered in relative energy. The low energy Ca(II) structures establish a coordination sphere with more ligands than do the low energy Mg(II) ion s

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1990.tb00244.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

One of the major proteins secreted from the rat seminal vesicle epithelium, namely SV‐IV, was shown to actin vitroas acyl donor and acceptor substrate for transglutaminase from both guinea pig liver and rat anterior prostate secretory fluid. Electrophoretic and chromatographic experiments indicated that the enzyme catalyzed the formation of multiple modified forms of SV‐IV. In the absence of small Mr amines, transglutaminase was able to produce at least six different molecular forms of the protein, half of which possessed an Mr higher than that of native SV‐IV. These findings suggested that a variable number of intermolecular, and perhaps intramolecular, crosslinks were formed between one or both glutamine residues and one or more lysine residues occurring in the SV‐IV polypeptide chain. In addition, at least three modified forms of the protein were produced by transglutaminase in the presence of high concentrations of spermidine, thus indicating the formation of different (γ‐glutamyl) polyamine derivatives of SV‐IV. Rabbit uteroglobin and rat anterior prostate secretory protein(s) were also shown to be able to covalently bind spermidine in the presence of the enzyme. The possible biological significance of transglutaminase‐mediated modifications of SV‐IV, as well as of other proteins occurring in the mammal seminal flui

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1990.tb00245.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Two hexapeptide analogues of Substance P (6–11) have been synthesized. Replacement of Gly9by proline provides a peptide with tenfold enhanced selectivity for the NK‐1 receptor. The corresponding proline‐containing glycopeptide incorporating a β‐d‐glucopyranosyl residue linked to the side‐chain of Glus was 100 times more selective than Substance P for the s

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1990.tb00246.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Fluorescent, photoreactive, and biotinylated analogs of vasopressin have been prepared in which one of these three groups has been attached to a reactive amino group in either position 4 or position 7. Using solid phase methodology, we have synthesized two active parent compounds, [l‐desamino,4‐lysine,7‐hydroxy‐prolinelarginine vasopressin and [l‐desamino,7‐aminoproline]arginine vasopressin, and acylated them to obtain biotinyl, azidobenzoyl, and fluoresceinyl derivatives. We have also prepared analogs in which a “spacer arm” was inserted between lysine in position 4 and the marker group. Some of these derivatives have good antidiuretic activity and could be valuable probes in studying hormone‐receptor interaction and in receptor visualization

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1990.tb00247.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Syntheses of two asymmetrical cystine peptides with the amino acid residues 21–25/70–73 and 35–39/56–59, based on the linear amino acid sequence and the disulfide bond assignment in the β‐subunit of human choriogonadotropin (hCG‐β), are described. S‐trityl and S‐acetamidomethyl peptide fragments of each cystine peptide were prepared in solution phase and were subjected to oxidation with I2/MeOH to form the disulfide bridge. The cystine peptides were characterized by their amino acid analyses and fast atom bombardment mass spectrometry. Immunological characterization by several homologous radioimmunoas‐say systems showed that peptide 21–25/70–73 had significant hCG, hCG‐β, and hLH activities while peptide 35–39/56–59 failed

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1990.tb00248.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY