bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and bioactivity of some new N‐aryl/alkyl/cyclohexyl‐N′‐(2,3‐dihydro‐2‐oxo‐4H‐benz[e][1,3,2]oxazaphosphorin‐2‐yl) ureas
Authors: Kiran YB , Gunasekar D , Devendranath Reddy C , Suresh Reddy C , Tran Kevin , Le Thanh , Darrell Berlin K , Srinivasan S , Charitha Devi M 
Published: May 2005

AbstractSeveral new substituted oxazaphosphorinyl urea derivatives of the type RR′P(O)NHC(O)NHR″ were synthesized from α‐(3‐chloro‐4‐fluoroanilino)‐o‐cresol by reaction with chlorides of aryl/alkyl/cyclohexyl carbamidophosphoric acids in the presence of triethylamine at 0–50 °C. Their significant insecticidal and antimicrobial activity and promotion of Rhizobium bacteria growth in the soil without effect on the host tissue suggests their possible commercial application as ecofriendly pesticides and antimicrobial agents. Copyright © 2005 Society of Chemical Industry
Protein design as a challenge for peptide chemists
Authors: Tuchscherer Gabriele , Mutter Manfred 
Published: May 2005

AbstractAll efforts to turn the ultimate goal in protein de novo design into reality–the construction of new macromolecules with predetermined three‐dimensional structure and well‐defined functionality–failed because the mechanism of folding has still to be unravelled. In the present review, various attempts to apply synthetic tools for inducing native‐like structural features in peptides in order to bypass the folding problem are described. Besides well‐established methods for the nucleation and stabilization of secondary structures, e.g. α‐helices, β‐sheets and β‐turns, topological templates as ‘built‐in’ folding devices have more recently become the key elements for the induction of protein‐like folding units (template‐assembled synthetic proteins, TASP). Progress in the synthetic strategy and structural characterization of this new type of macromolecules opens the way for the design of functional TASP molecules.
N,O‐bisFmoc derivatives of N‐(2‐hydroxy‐4‐methoxybenzyl)‐amino acids: Useful intermediates in peptide synthesis
Authors: Johnson Tony , Quibell Martin , Sheppard Robert C. 
Published: May 2005

Abstract2‐Hydroxy‐4‐methoxybenzyl‐amino acid residues inhibit interchain association in solid phase peptide synthesis. They are easily introduced through their N,O‐bisFmoc derivatives. Preparation of a range of these derivatives is described.
Binary synthesis of multicomponent peptide mixtures by the portioning–mixing technique
Authors: Sebestyén Ferenc , Szalatnyai Tüunde , Durgo Joseph A. , Furka Árpád 
Published: May 2005

AbstractBy introducing a new operation (non‐coupling), our portioning–mixing method has become suitable for preparing binary peptide libraries. We demonstrate that all the expected components of a simple library are present in the mixture. The number of components in such libraries, the molar ratio of peptides as well as the possibilities of screening are discussed.
Synthesis, characterization and biocompatibility of PEGA resins
Authors: Auzanneau France‐Isabelle , Meldal Morten , Bock Klaus 
Published: May 2005

AbstractThree types of beaded polyethylene glycol polyacrylamide copolymers (PEGA) with a high content of polyethylene glycol (PEG) were synthesized by inverse suspension polymerization and characterized for peptide synthesis and with respect to their physical properties. Several peptides of high purity have been synthesized on the resin. The properties which were determined were loading of amino group, swelling, bead size distribution, porosity, flexibility and compatibility with active biomolecules. A loading of 0.35 mmol/g has been obtained and the swelling was excellent in solvents of various polarities ranging from water to dichloromethane. The 13C‐NMR T1‐relaxation times of a resin containing a peptide were determined in DMSO‐d6 and the resin was found to exhibit a behaviour similar to the components in free solution.
Synthesis and conformational studies of peptides containing TOAC, a spin‐labelled Cα,α‐disubstituted glycine
Authors: Toniolo Claudio , Valente Ezio , Formaggio Fernando , Crisma Marco , Pilloni Giuseppe , Corvaja Carlo , Toffoletti Antonio , Martinez Gary V. , Hanson M. Paul , Millhauser Glenn L. , George Clifford , Flippen‐Anderson Judith L. 
Published: May 2005

AbstractA variety of host L‐alanine homo‐peptides (to the pentamer) containing one or two spin‐labelled TOAC (2,2,6,6‐tetramethylpiperidine‐1‐oxyl‐4‐amino‐4‐carboxylic acid) residues were synthesized by solution methods and fully characterized. The conformational features of the terminally blocked, doubly spin‐labelled–TOAC–(Ala)2–TOAC–Ala– pentapeptide were examined in the crystal state by X‐ray diffraction and in solution using a combination of techniques (Fourier transform infrared, circular dichroism, cyclic voltammetry and electron spin resonance) in comparison with singly labelled shorter peptides. The 310‐helical structure of the pentapeptide, promoted by the two Cα,α‐disubstituted glycines under favourable experimental conditions, allows an interaction to take place between the two nitroxide TOAC side chains spaced by one turn of the helix. Taken together, these results suggest that TOAC is an excellent probe for exploring bends and helices in doubly labelled peptides.
Synthesis and lodination of human (phenylalanine13, tyrosine19) melanin‐concentrating hormone for radioreceptor assay
Authors: Drozdz Roma , Eberle Alex N. 
Published: May 2005

AbstractAn analogue of human melanin‐concentrating hormone (MCH) suitable for radioiodination was designed in which Tyr13 and Val19 of the natural peptide were replaced by phenylalanyl and tyrosyl residues: [Phe13, Tyr19] ‐MCH. The peptide was synthesized by the continuous‐flow solid‐phase methodology using Fmocstrategy and Polyhipe PA 500 and PEG‐PS resins. The linear MCH peptides with either acetamidomethyl‐protected or free cysteinyl residues were purified to homogeneity and cyclized by iodine oxidation, yielding the final product with the correct molecular weight of 2434.61. Radioiodination of the C‐terminal tyrosine was carried out enzymatically using solid‐phase bound glucose oxidase/lactoperoxidase, followed by purification on a reversed‐phase mini‐column and by high‐pressure liquid chromatography. The resulting [125I]‐[Phe13, Tyr19]‐MCH tracer was the first radiolabelled MCH peptide suitable for radioreceptor assay: saturation binding analysis using mouse G4F‐7 melanoma cells demonstrated the presence of 1090 MCH receptors per cell. The dissociation constant (KD) was 1.18 × 10−10 M, indicating high‐affinity MCH receptors on these cells. MCH receptors were also found in other cell lines such as mouse B16‐F1 and G4F and human RE melanoma cells as well as in PC12 and COS‐7 cells. Competition binding analyses with a number of other peptides such as α‐MSH, neuropeptide Y, substance P and pituitary adenylate cyclase activating peptide, demonstrated that the binding to the MCH receptor is specific. Atrial natriuretic factor was found to be a weak competitor of MCH, indicating topological similarities between MCH and ANF when interacting with MCH receptors.
An exploration of the effects of L‐ and D‐tetrahydroisoquinoline‐3‐carboxylic acid substitutions at positions 2,3 and 7 in cyclic and linear antagonists of vasopressin and oxytocin and at position 3 in arginine vasopressin
Authors: Manning Maurice , Cheng Ling Ling , Stoev Stoytcho , Bankowski Krzysztof , Przybyiski Jozef , Klis Wieslaw A. , Sawyer Wilbur H. , Wo Nga Ching , Chan W. Y. 
Published: May 2005

AbstractWe have investigated the effects of mono‐substitutions with the conformationally restricted amino acid, 1,2,3,4 tetrahydroisoquinoline‐3‐carboxylic acid (Tic) at position 3 in arginine vasopressin (AVP), at positions 2, 3 and 7 in potent non‐selective cyclic AVP V2/V1a antagonists, in potent and selective cyclic and linear AVP V1a antagonists, in a potent and selective oxytocin antagonist and in a new potent linear oxytocin antagonist Phaa‐D‐Tyr(Me)‐Ile‐Val‐Asn‐Orn‐Pro‐Orn‐NH2 (10). We report here the solid‐phase synthesis of peptide 10 together with the following Tic‐substituted peptides: 1, [Tic3]AVP; 2, d(CH2)5[D‐Tic2]VAVP; 3, d(CH2)5[D‐Tyr(Et)2Tic3]VAVP; 4, d(CH2)5[Tic2Ala‐NH29]AVP; 5, d(CH2)5[Tyr(Me)2, Tic3, Ala‐NH29]AVP; 6, d(CH2)5 [Tyr(Me)2, Tic7]AVP; 7, Phaa‐D‐Tyr(Me)‐Phe‐Gln‐Asn‐Lys‐Tic‐Arg‐NH2; 8, desGly‐NH2,d(CH2)5[Tic2,Thr4]OVT; 9, desGly‐NH2d(CH2)5[Tyr(Me)2Thr4, Tic7]OVT; 11, Phaa‐D‐Tic‐Ile‐Val‐Asn‐Orn‐Pro‐Orn‐NH2, using previously described methods. The protected precursors were synthesized by the solid‐phase method, cleaved, purified and deblocked with sodium in liquid ammonia to give the free peptides 1–11 which were purified by methods previously described. Peptides 1–11 were examined for agonistic and antagonistic potency in oxytocic (in vitro, without Mg2+) and AVP antidiuretic (V2‐receptor) and vasopressor (V1a‐receptor) assays. Tic3 substitution in AVP led to drastic losses of V2, V1a and oxytocic agonistc activities in peptide 1.L‐ and D‐Tic2 substitutions led to drastic losses of anti‐V2/anti‐V1a and anti‐oxytocic potencies in peptides 2, 4, 8 and 11 (peptide 2 retained substantial anti‐oxytocic potency; pA2 = 7.25 ± 0.25). Whereas Tic3 substitution in the selective V1a antagonist d(CH2)5[Tyr(Me)2, Ala‐NH29]APV(C) led to a drastic reduction in anti‐V1a potency (from anti‐V1a pA2) 8.75 to 6.37 for peptide 5, remarkably, Tic3 substitution in the V2/V1a antagonist d(CH2)5[D‐Tyr(Et)2]VAVP(B) led to full retention of anti‐V2 potency and a 95% reduction in anti‐V1a potency. With an anti‐V2 pA2 = 7.69 ± 0.05 and anti‐V1a pA2 = 6.95 ± 0.03, d(CH2)5[D‐Tyr(Et)2,Tic3]VAVP exhibits a 13‐fold gain in anti‐V2/anti‐V1a selectivity compared to (B). Tic7 substitutions are very well tolerated in peptides 6, 7 and 9 with excellent retention of the characteristic potencies of the parent peptides. The findings on the effects of Tic3 substitutions reported here may provide promising leads to the design of more selective and possibly orally active V2 antagonists for use as pharmacological tools and as therapeutic clinical agents for the treatment of the syndrome of the inappropriate secretion of antidiuretic hormone (SIADH).
Multiple synthesis by the multipin method as a methodological tool
Authors: Bray Andrew M. , Valerio Robert M. , Dipasquale Angela J. , Greig Joy , Maeji N. Joe 
Published: May 2005

AbstractThe multipin method of peptide synthesis is demonstrated as a potent methodological tool, where large numbers of comparative studies can be performed concurrently. Two studies are presented. In each study, the test peptides were simultaneously synthesized, and the products examined by high throughput ion spray mass spectrometry and reverse‐phase HPLC. In the first study, comprising 24 experiments, peptides 1 (AELFSTHYLAFKEDYSQ‐NH2) and 2 (LKDFRVYFREGRDQLWKGPG‐NH2) were prepared using Fmoc‐Axx/BOP/HOBt/NMM (100: 100: 100: 150 mM) and Fmoc‐Axx/HATU/HOAt/NMM (100: 100: 100: 150 mM) with 60.90 and 120 min coupling times. The two reagent combinations were found to give comparable results. The second study compared the N‐terminal coupling of Fmoc‐Asn‐OH, Fmoc‐Asn(Mbh)‐OH, Fmoc‐Asn(Mtt)‐OH, Fmoc‐Asn(Tmob)‐OH and Fmoc‐Asn(Trt)‐OH in the synthesis of seven test peptides: 3, NVQAAIDYIG‐cyclo(Kp); 4, NTVQAAIDYIG‐cyclo(KF); 5, NRVYVHPFNL; 6, NRVYVHPFHL: 7, NEAYVHDAPVRSLN: 8, NQLVVPSEGLYLIYSQVLFK. 9, NPNANPNANPNA. A total of 33 experiments were performed. Peptides 3 and 4 were selected to highlight the effect of steric bulk of each Asn derivative on coupling efficiency. Reagent efficiency, as measured by target peptide purity, was as follows: Fmoc‐Asn(Tmob)‐OH > Fmoc‐Asn‐OH > Fmoc‐Asn(Mtt)‐OH = Fmoc‐Asn(Trt)‐OH > Fmoc‐Asn(Mbh)‐OH.
Antiovulatory antagonists of LHRH related to antide
Authors: Flouret George , Arnold Zdzislaw S. , Majewski Tadeusz , Petousis Nikolaos H. , Mahan Kevin , Farooqui Firdous , Blum Katherine A. , Konopinska Danuta , Natarajan Swaminathan , Crich David 
Published: May 2005

AbstractWe report 104 analogues of the potent antiovulatory antagonist of LHRH, N‐Ac‐D‐Nal‐D‐Cpa‐D‐Pal‐Ser‐Lys(Nic)‐D‐Lys(Nic)‐Leu‐Ilys‐Pro‐D‐Ala‐NH2, Antide. We replaced the Nic group in Antide with other acyl substituents to modulate size, hydrophilicity or basicity of the molecule, we also replaced th Lys residues with shorter basic amino acids, and made cyclic 5/6 analogues as well as position 5 or 6 dimers. We substituted Ilys8 with other alkyl groups and acyl derivatives. When injected in 0.1% DMSO in water in a typical antiovulatory (AO) assay, Antide gives six rats ovulating out of eight (6/8) at 2 μg, 4/8 at 4 μg, and the histamine release assay (HRA), ED50 is >300 μg/ml; [Lys(N‐Isobutyl)8]Antide gave 2/8 at 2 μg/rat; [Lys (8‐Qis)5]Antide gave 1/8 at 1 μg, and 0/8 at 2 μg, and in the HRA ED50, 22 μg/ml; [D‐Lys(8‐Qis)6]Antide gave 4/8 at 1 μg and 0/8 at 2 μg, and in the HRA, ED50 was 27 μg/ml; [Lys(8‐Qic)8] gave 5/8 at 1 μg, 1/8 at 2 μg/ [Lys(2‐Pyc)5]Antide gave 5/8 at 1 μg and 0/8 at 2 μg, and in the HRA ED50 was 116 μg/ml; [D‐Lys (2‐Pyc)6]Antide gave 3/8 at 1 μg, and in the HRA, ED50 was 100 ‐ >300 μg/ml; [Lys(2‐Pyc)5,D‐Lys(2‐Pyc)6]Antide gave 2/8 at 1 μg. The substitutions of the Nic groups of Antide at Lys5 or D‐Lys6 with 8‐Qis or with 2‐Pyc groups seem to give highly potent antiovulatory antagonists of LHRH and constitute significant new leads to generate potent antiovulatory compounds endowed with moderate or low histamine release.
A synthetic substrate assay for the gamma‐secretase of the β‐A4 amyloid of alzheimer's disease
Authors: Evin Geneviève , Beyreuther Konrad , Masters Colin L. 
Published: May 2005

Abstractγ‐secretase, the endoprotease which releases the C‐terminus of βA4 amyloid peptide, cleaves within the hydrophobic transmembrane domain of the amyloid precursor protein. In order to obtain a substrate for γ‐secretase, a dodecapeptide which spans the cleavage site was synthesized, labelled with 125‐iodine and conjugated to an agarose gel. A radiometric solid‐phase assay was developed using this immobilized substrate. Peptide products were separated by reverse‐phase HPLC and TLC to allow characterization of the cleavage site(s).
Immunogenicity of dinitrocarboxyphenylated melittin: The influence of C‐terminal chain shortening, N‐terminal substitution and prolin insertion at positions 5 and 10
Authors: Zhao Zhenjun , Rolli Hanspeter , Schneider Conrad H. 
Published: May 2005

AbstractPeptides derived from the bee‐venom melittin were fitted with the haptenic group dinitrocarboxyphenyl(Dncp) and tested in out‐bred guinea pigs for immunogenicity by measuring the IgG anti‐Dncp antibody response by ELISA. Dncp‐conjugates comprising virtually the entire melittin proved to be strong immunogens producing antibody responses comparable to those of proteins. Weak responses were obtained with considerably shortened seqences. Conjugates with N‐terminal Dncp gave markedly reduced antibody responses compared to peptides with C‐terminal Dncp. An N‐terminal biotinyl substituent abolished the immune response whereas N‐terminal lauryl and caprylyl had little effect. Insertion of L‐proline into a hexadecapeptide conjugate abolishing the possibility of helix formation gave an immunogen to which individual animals clearly responded on a low level. Oligomerisation, but not the cytolytic activity of melittin peptides, may contribute to the immunogenicities observed.
Highly potent side chain–main chain cyclized dermorphin–deltorphin analogues: An integrated approach including synthesis, bioassays, NMR spectroscopy and molecular modelling
Authors: Ro Seonggu , Zhu Qin , Lee Chang‐Woo , Goodman Murray , Darlak Krzysztof , Spatola Arno F. , Chung Nga N. , Schiller Peter W. , Malmberg Annika B. , Yaksh Tony L. , Burks Thomas F. 
Published: May 2005

AbstractOur continuing efforts to study structure–activity relationships of peptide opioids have resulted in the synthesis of a series of cyclic opioids related to dermorphins and deltorphins. The biological activities of the compounds have been determined and the conformational analyses carried out using 1H‐NMR spectroscopy and molecular modelling. The three compounds in the series Tyr‐c[D‐Orn‐Phe‐Ala], Tyr‐c[D‐Lys‐Phe‐Ala], and Tyr‐c[A2Bu‐Phe‐Ala‐Leu] are cyclized via a lactam bridge from the side‐chain of the residue at the second position with the carboxyl terminus of each compound. The molecules incorporate 12‐, 13‐ and 14‐membered rings, respectively. They include a phenylalanine at the third position which is a distinguishing characteristic of dermorphins and deltorphins. The guinea pig ileum and mouse vas deferens assays show that the compounds are highly active at both μ‐ and δ‐opioid receptors. The compounds are all highly effective antinociceptive agents as measured by the intrathecal rat hot plate test. Conformational analyses of the molecules indicate that they can adopt topochemical arrays required for bioactivity at both μ‐ and δ‐receptors which explains their high activity in both guinea pig ileum and mouse vas deferens in vitro assays. The results support our models for μ‐ and δ‐receptor activity for constrained peptide opioids.
Solid‐Phase synthesis of peptide nucleic acids
Authors: Christensen Leif , Fitzpatrick Richard , Gildea Brian , Petersen Kenneth H. , Hansen Henrik F. , Koch Troels , Egholm Michael , Buchardt Ole , Nielsen Peter E. , Coull James , Berg Rolf H. 
Published: May 2005

AbstractPeptide nucleic acids (PNA) were synthesized by a modified Merrifield method using several improvements. Activation by O‐(benzotriazol‐1‐yl)‐1,1,3,3‐tetramethyluronium hexafluorophosphate in combination with in situ neutralization of the resin allowed efficient coupling of all four Boc‐protected PNA monomers within 30 min. HPLC analysis of the crude product obtained from a fully automated synthesis of the model PNA oligomer H‐CGGACTAAGTCCATTGC‐Gly‐NH2, indicated an average yield per synthetic cycle of 97.1%. N1‐benzyloxycarbonyl‐N63‐methylimidazole triflate substantially outperformed acetic anhydride as a capping reagent. The resin‐bound PNAs were successfully cleaved by the ‘low–high’ trifluoromethanesulphonic acid procedure.
Synthetic S‐(2,3‐dihydroxypropyl)‐cysteinyl peptides derived from the N‐terminus of the cytochrome subunit of the photoreaction centre of Rhodopseudomonas viridis enhance murine splenocyte proliferation
Authors: Metzger Jörg W. , Beck‐Sickinger Annette G. , Loeit Manuel , Eckert Marianne , Bessler Wolfgang G. , Jung Günther 
Published: May 2005

AbstractVarious lipopeptides representing the N‐terminal part of the cytochrome subunit of the photosynthetic reaction centre from the purple bacterium Rhodopseudomonas virdis were prepared by solid‐phase peptide synthesis. These lipopeptides consisted of a S‐[2,3‐dihydroxypropyl]‐cysteinyl (Dhc) residue N‐terminally coupled to the nonapeptide FEPPPATTT. Different numbers of palmitoyl (Pam) chains were attached to Dhc via ester and/or amide bonds. The lipopeptide Dhc(Pam)2‐FEPPPATTT containing two ester‐bonded palmitoyl residues and a free N‐chain lipopeptide Pam‐Dhc(Pam)‐FEPPPATTT containing one amide‐ and one ester‐bonded palmitoyl residues, the two‐chain lipopeptide Pam‐Dhc(Pam)‐FEPPPATTT containing one amide‐ and one ester‐bonded palmitoyl residue, and the N‐terminally elongated lipopeptide SLVAG‐Dhc(Pam)2‐FEPPPATTT were less active. The nonapeptide FEPPPATTT and the decapeptide Dhc‐FEPPPATTT were only merginal splenocyte activators, even at concentrations as high as 1 μM. Thus, lipopeptide Dhc(Pam)2‐FEPPPATTT constitutes the first potent splenocyte stimulating Dhc‐lipopeptide described so far that contains only two fatty acid residues.
Anchor‐linked intermediates in peptide amide synthesis are caused by dimeric anchors on the solid supports
Authors: Flechsler Insa , Beck‐Sickinger Annette G. , Stephan Holger , Sheppard Robert , Jung Günther 
Published: May 2005

AbstractCleavage and kinetic studies have been carried out using commercially obtained H‐Tyr(tBu)‐5‐(4′‐aminomethyl‐3′,5′‐dimethoxyphenoxy)valeric acid‐TentaGelS (H‐Tyr(tBu)‐4‐ADPV‐TentaGelS) and H‐Tyr (tBu)‐4‐ADPV‐Ala‐aminomethyl‐resin (H‐Tyr(tBu)‐4‐ADPV‐AM‐resin) prepared from commercially available resin and loaded with commercially available Fmoc‐4‐ADPV‐OH amide anchor. Cleavage with pure trifluoroacetic acid (TFA) gave the intermediate H‐Tyr‐4‐ADPV‐NH2, which was then degraded to H‐Tyr‐NH2, and cleavage with TFA/dichloromethane (1:9) yielded H‐Tyr‐4‐ADPV‐NH2 which could be isolated in preparative amounts. Cleavage reactions with 15N‐labelled H‐Ala‐4‐ADPV‐[15N]‐Gly‐AM‐resin yielded the intermediate H‐Ala‐4‐ADPV‐NH2, which contained no 15N as demonstrated by 1H‐NMR. The analysis of the commercial Fmoc‐4‐ADPV‐OH amide anchor showed the presence of Fmoc‐4‐ADPV‐4‐ADPV‐OH as an impurity in high amounts. This dimeric anchor molecule is the cause of formation of the anchor‐linked peptide intermediate obtained during the cleavage from the resin. The particularly high acid‐lability of the amide bond between the two ADPV moieties was utilized to synthesize sidechain and C‐terminally 4‐ADPV protected pentagastrin on a double‐anchor resin, and to cleave it using 5% trifluoroacetic acid in dichloromethane. This method may offer a new way for the synthesis of protected peptide amides with improved solubility to be used in fragment condensation.
Determination of disulphide bridges in PG‐2, an antimicrobial peptide from porcine leukocytes
Authors: Harwig Sylvia S. L. , Swiderek Kristine M. , Lee Terry D. , Lehrer Robert I. 
Published: May 2005

AbstractWe determined the cysteine connectivity of protegrin PG‐2, a leukocyte‐derived antimicrobial peptide, by performing sequential enzyme digestions with chymotrypsin and thermolysin, and monitoring each digest by direct liquid chromatography–electrospray mass spectrometric analysis. This approach resolved the disulphide pairing pattern unambiguously with only picomolar amounts of PG‐2. The inferred cysteine connectivity was confirmed by traditional amino acid composition analyses using nanomolar amounts of the protegrin. The results suggest that protegrins will assume a tachyplesin‐like, disulphide‐stabilized antiparallel β‐sheet configuration in solution.
Identification of avidin and streptavidin binding motifs among peptides selected from a synthetic peptide library consisting solely of D‐amino acids
Authors: Gissel Birgitte , Jensen Martin Roland , Gregorius Klaus , Elsner Henrik I. , Svendsen Ib , Mouritsen Søren 
Published: May 2005

AbstractPeptides consisting solely of D‐amino acids (D‐peptides) as opposed to their L‐counterparts (L‐peptides) are resistant towards proteolytic degradation in the organism and may therefore be useful in future efforts to develop new stable peptide‐based drugs. Using the random synthetic peptide library technique several L‐ and D‐peptides, capable of binding to both avidin and streptavidin, were found. The L‐peptides contained the previously described HPQ/M motifis, and among the D‐peptides three binding motifs could be identified, of which the most frequently found one contained an N‐terminal aliphatic hydrophobic amino acid (V, L or I) and an aromatic amino acid (Y or F) on the second position. At the third position in this motif several different amino acid residues were found, although N was the most frequent. Peptides representing two of the D‐motifs were synthesized as well as peptides containing the HPQ/M motifs, and their binding properties were examined. Although the D‐peptides were originally selected using avidin they also inhibited binding between immobilized biotin and soluble streptavidin as well as avidin. The IC50 of some of the peptides were approximately 105 times higher than the IC50 for biotin but some had a lower IC50 than iminobiotin. The D‐peptides, which were originally selected from the library using avidin, could also inhibit the binding between streptavidin and biotin. Likewise, L‐peptides selected from a library screened with streptavidin, could inhibit the binding of both streptavidin and avidin to immobilized biotin. Furthermore, the D‐peptide, VFSVQSGS, as well as biotin could inhibit binding of streptavidin to an immobilized L‐peptide (RYHPQSGS). This indicates that the biotin‐like structure mimicked by these two seemingly very different peptides may react with the same binding sites in the streptavidin molecule.