ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1991.tb00724.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

A 30‐residue peptide [YAA(KALA)6LAA] with an amphipathic helix repeat unit of Lys‐Ala‐Leu‐Ala (KALA) was synthesized as both thel‐ and thed‐isomer. The peptide was shown to form α‐helices and lyse lipid vesicles in a pH dependent fashion. The calculated helical amphipathic moment is + 1.19 kcal/ residue and the mean residue hydrophobicity is +0.4 kcal/residue. The formation of α‐helices as the pH is increased is similar to poly‐lysine, yielding a pK of 10.2. Though not toxic when fed to insects, KALA killedSpodoptera frugiperdacells at low doses andManduca sextal

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1991.tb00725.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The immunodominant epitope ofPlasmodium vivax, one of the major causative agents of malaria in man, consists of the tandem repetitions of a nonapeptide sequence, AspArgAlaAsp/AlaGlyGlnProAlaGly, with Asp (variant d) or Ala (variant a), in the fourth position. Synthetic peptides corresponding to theP. vivaxepitope, containing a different number of nonapeptide sequences, were prepared by solid‐phase synthesis according to the Fmoc‐polyamide method. Three peptides, containing 1, 2, and 4 copies of the d variant, were assembled on the gel polymer; none of these peptides, however, was suitable forP. vivaxsero‐epidemiology. A 45‐peptide containing both the d and a variants, ddaad, was prepared by continuous‐flow Fmoc‐polyamide(flow‐polyamide).Among the cleavage procedures evaluated for the removal of the five Mtr groups only TFMSA/TFA/ 1,2‐ethanedithiol (1:89:10 by vol.) brought deblocking to completion; a substantial level of impurities originated, however, from these procedures. The product was purified by reversed‐phasedisplacement chromatography, a technique only recently applied to peptides, which shows distinct advantages over conventional, linear elution chromatography. In a single experiment, 107 mg of the crude mixture were loaded onto an analytical column (250 × 4 mm), obtaining in purified form 85% of the desired material present in the sample. An ELISA test base on the ddaad peptide was developed and is being applied to the sero‐epidemiolo

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1991.tb00726.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The incubation of a solution of the human growth hormone releasing factor analog, [Leu27] hGRF(1‐32)NH2at pH 7.4 and 37°, resulted in extensive degradation of the sample. The major degradation products were identified as the peptides [β‐Asp8, Leu27] hGRF(l‐32)NH2and [α‐Asp8, Leu27] hGRF(1‐32)NH2, produced by deamidation of the Asn8residue. When tested as growth hormone (GH) secretagogues in cultured bovine anterior pituitary cells, [β‐Asp8, Leu27] hGRF(l‐32)NH2was estimated to be 400‐500 times less potent than the parent Asn8peptide, while [2‐Asp8, Leu27] hGRF(l‐32)NH2was calculated to be 25 times less potent than the parent Asn8peptide. Three additional analogs of [Leu27] hGRF(1‐32)NH2containing either Ser or Asn at positions 8 and 28 were prepared and evaluated for their GH releasing activity and stability in aqueous phosphate buffer (pH 7.4, 37°). Based on disappearance kinetics, [Leu27] hGRF(1‐32)NH2had a half‐life of 202 h while the other analogs had the following half‐lives: [Leu27, Asn28] hGRF(1‐32)NH:(150h); [Ser8, Leu27, Asn28] hGRF(l‐32)NH2(746h); and [Ser8, Leu27] hGRF(1‐32)NH2(1550 h). After 14 days, incubated samples of the Asn8analogs lost GH releasing potency, while the Ser8analogs retained full potency. The potential for loss of biological activity brought about by deamidation of other engineered peptides and protein

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1991.tb00727.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Analogues of angiotensin II with cyclohexylalanine (Cha) at position 4 or 8, and analogues of the competitive (type II) angiotensin antagonist [Sar1,Tyr(Me)4]ANG II (Sarmesin) with Cha at position 8, have been prepared by the solid phase method and purified by reversed‐phase HPLC. Analogues of ANG II with Cha at position 8 in which the position 1 residue was substituted with sarcosine (Sar) or amino‐isobutyric acid (Aib) or was deleted (Des), were slowly reversing (Type I) antagonists with „pA2” values in the rat isolated uterus assay of ∼ 8.5. The additional substitution of Tyr(Me) for Tyr at position 4 of these peptides gave reversible competitive (Type I/II) antagonists with pA2values of 6.7, 5.8, and<5, while substitution of Phe for Tyr gave pA2values of 7.4, 6.7, and<5, respectively. All 19 peptides synthesized in this study had low intrinsic agonist activity in the rat isolated uterus assay except for the type I antagonists [Sar1,Cha8]ANG II (7%), [Aib1, Cha8]ANG II (12%) and [Des1,Cha8]ANG II (20%). These data illustrate that the substitution of Cha at position 8 of ANG II analogues produces potent antagonists; however, Type I antagonists retain significant agonist activity whereas Type I/II antagonists do not. In contrast, substitution of Cha at position 4 in a variety of ANG II analogues resulted in severely diminished biological activity, illustrating that the presence of an aromatic ring quadrupole at position 4 is obligatory for receptor binding and

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1991.tb00728.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

A new synthetic functionalized antigen carrier is described. It consists of a core of seven branched lysine residues, of which each of the fourN‐terminal lysine residues contains twoN‐(S‐acetylmercaptoacetyl)‐glutamyl residues. After removal of the protectingS‐acetyl groups affording eight thiol functions, the carrier can easily be conjugated to a properly functionalized antigen, e.g. anS‐(Npys)‐cysteinyl peptide, thus affording a high molecular weight conjugate with an unusually high an

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1991.tb00729.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

γ‐Carboxyglutamic acid (Gla) is believed to bind Ca [II] ions and Mg [II]ions in prothrombin and other coagulation proteins. Binding constants for H+, Ca [II] ions, and Mg [II]ions to Gla‐containing peptides are determined using pH and ion selective electrode titrations. The binding constants for peptides containing a single Gla residue are similar to the constants for malonic acid. Peptides containing two Gla residues in sequence (di‐Gla peptides) bind Ca [II] ions and Mg [II]ions more strongly. KMgLfor the di‐Gla peptides is similar to the site‐binding constant for Ca [II] ions in denatured BF1. These di‐Gla peptides may be useful analogs for metal binding by the disordered Gla d

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1991.tb00730.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The crystal structure of the tBuCO‐d,l‐Ala‐Δz‐Phe‐NHiPr dipeptide has been solved by X‐ray diffraction. The peptide crystallizes in monoclinic space group P2JC with a = 13.445 (3) Å, b = 35.088 (4) Å, c = 14.755(3) Å, β= 116.73(1)°, Z = 12 and dc= 1.151 g.cm−3. The three independent molecules per asymmetric unit accommodate a βII‐folded conformation, but only one of them contains the typical i + 3 → i interaction characterizing a β‐turn. In the other two molecules, the N…O distance exceeds 3.2 Å, a value generally considered the upper limit for hydrogen bonds in peptides. In solution, the βII‐turn co

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1991.tb00731.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The synthesis and characterization of lipopeptides consisting of the lipoamino acidN‐palmitoyl‐S‐[2,3‐bis(palmitoyloxy)‐(2RS)‐propyl]‐[R]‐cysteine (Pam,Cys‐OH) and different peptide segments and/or spacer molecules is described. Pam,Cys‐peptides, which are derived from the immunologically active TV‐terminus of bacterial lipoprotein, were obtained either by solution or solid phase peptide synthesis. In particular, the amphiphilic and water‐soluble lipohexapeptides Pam3Cys‐Ser‐(Lys)4and Pam3Cys‐Ser‐(Glu)4proved to be potent macrophage and B‐cell activators and non‐toxic, non‐pyrogenic immune adjuvants in combination with or cova

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1991.tb00732.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The solid‐phase synthesis, photolytic detachment from the solid support and purification in solution, of a fully‐protected octapeptide containing a methionine residue (protected as the sulphoxide) is described. Protection of methionine in this manner avoids problems associated with the oxidation of this residue during the photolysis. The peptide has been purified by medium pressure liquid chromatography using solvent mixtures containing a high proportion of dimethylformamide in order to avoid precipitation of the peptide on the col

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1991.tb00733.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY