Janusz Zabrocki

Janusz Zabrocki
Lodz University of Technology · Institute of Organic Chemistry

Professor

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144
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Publications

Publications (144)
Article
Full-text available
The devastating Varroa mite (Varroa destructor Anderson and Trueman) is an obligatory ectoparasite of the honey bee, contributing to significant colony losses in North America and throughout the world. The limited number of conventional acaricides to reduce Varroa mites and prevent disease in honey bee colonies is challenged with wide-spread resist...
Article
Full-text available
The core of Cyclolinopeptide A (CLA, cyclo(LIILVPPFF)), responsible for its high immunosuppressive activity, contains a Pro-Pro-Phe-Phe sequence. A newly synthesized cyclic tetrapeptide, cyclo(Pro-Pro-β3-HoPhe-Phe) (denoted as 4B8M) bearing the active sequence of CLA, was recently shown to exhibit a wide array of anti-inflammatory properties in mou...
Article
Full-text available
Insect CAPA neuropeptides are considered to affect water and ion balance by mediating the physiological metabolism activities of the Malpighian tubules. In previous studies, the CAPA-PK analogue 1895 (2Abf-Suc-FGPRLamide) was reported to decrease aphid fitness when administered through micro-injection or via topical application. However, a further...
Article
Full-text available
A facile solid-phase synthetic method for incorporating the imidazoline ring motif, a surrogate for a trans peptide bond, into bioactive peptides is reported. The example described is the synthesis of an imidazoline peptidomimetic analog of an insect pyrokinin neuropeptide via a cyclization reaction of an iminium salt generated from the preceding a...
Preprint
A facile solid-phase synthetic method for incorporating the imidazoline ring motif, a surrogate for a trans peptide bond, into bioactive peptides is reported. The example described is the synthesis of an imidazoline peptidomimetic analog of an insect pyrokinin neuropeptide via a cyclization reaction of an iminium salt generated from the preceding a...
Article
Full-text available
Peptides are fragments of proteins that carry out biological functions. They act as signaling entities via all domains of life and interfere with protein-protein interactions, which are indispensable in bio-processes. Short peptides include fundamental molecular information for a prelude to the symphony of life. They have aroused considerable inter...
Article
Full-text available
W.M.W.) † Dedicated to Professor Garland Marshall on the occasion of his 80th birthday. Citation: Apostolopoulos, V.; Bojarska, J.; Chai, T.-T.; Elnagdy, S.; Kaczmarek, K.; Matsoukas, J.; New, R., Parang, K.; Lopez, O.P.; Parhiz, H.; et al. A Global Review on Short Peptides: Frontiers and Perspectives. Molecules 2021, 26, 430. https://doi.
Article
Full-text available
A cyclic tetrapeptide Pro-Pro-Pheβ3ho-Phe (4B8M) was tested for immunosuppressive activity and potential therapeutic utility in several in vitro and in vivo mouse and human models. The tetrapeptide was less toxic for mouse splenocytes in comparison to cyclosporine A (CsA) and a parent cyclolinopeptide (CLA). The tetrapeptide demonstrated potent ant...
Article
The synthesis of new analogues of cyclolinopeptide A (CLA) and their linear precursors modified with (R)- and (S)-4-methylpseudoproline in the Pro³-Pro⁴ fragment are presented. The peptides were tested in comparison with cyclosporine A (CsA) in concanavalin A (Con A) and pokeweed mitogen (PWM)-induced mouse splenocyte proliferation and in secondary...
Article
Neuropeptides belonging to the adipokinetic hormone (AKH) family elicit metabolic effects as their main function in insects, by mobilizing trehalose, diacylgycerol, or proline, which are released from the fat body into the hemolymph as energy sources for muscle contraction required for energy-intensive processes, such as locomotion. One of the AKHs...
Article
Full-text available
Recently, fluorenylmethoxycarbonyl (Fmoc) amino acids ( e.g. Fmoc–tyrosine or Fmoc–phenylalanine) have attracted growing interest in biomedical research and industry, with special emphasis directed towards the design and development of novel effective hydrogelators, biomaterials or therapeutics. With this in mind, a systematic knowledge of the stru...
Article
Full-text available
The success of innovative drugs depends on an interdisciplinary and holistic approach to their design and development. The supramolecular architecture of living systems is controlled by non-covalent interactions to a very large extent. The latter are prone to extensive cooperation and like a virtuoso play a symphony of life. Thus, the design of eff...
Article
Full-text available
BACKGROUND Kinins are multifunctional neuropeptides that regulate key insect physiological processes such as diuresis, feeding, and ecdysis. However, the physiological roles of kinins in ticks are unclear. Furthermore, ticks have an expanded number of kinin paracopies in the kinin gene. Silencing the kinin receptor (KR) in females of Rhipicephalus...
Article
The title compound, N-benzoyl-2′-hydroxy-3-methylisovaline, representing synthon polymorphism, can be interesting inter alia from the point of view of modern supramolecular biofunctional materials. A novel crystalline phase (1) was successfully synthesized and its solid-state supramolecular architecture was comprehensively compared with the previou...
Article
Insect kinins modulate aspects of diuresis, digestion, development, and sugar taste perception in tarsi and labellar sensilla in mosquitoes. They are, however, subject to rapid biological degradation by endogenous invertebrate peptidases. A series of α-aminoisobutyric (Aib) acid-containing insect kinin analogs incorporating sequences native to the...
Article
Full-text available
Natalisins (NTLs) are conservative neuropeptides, which are only found in arthropods and are documented to regulate reproductive behaviors in insects. In our previous study, we have confirmed that NTLs regulate the reproductive process in an important agricultural pest, Bactrocera dorsalis (Hendel). Hence, in this study, to further confirm the in v...
Data
Sequence of the B. dorsalis NTLR cDNA and the corresponding amino acid sequence. The annealing sites of the qRT-PCR primers are denoted in bold and underlined, while the annealing sites of the primers for the RNAi-constructs are denoted in bold and dashed underlined in the cDNA sequence. (JPG)
Article
Cyclolinopeptide A (CLA), an immunosuppressive nonapeptide derived from linen seeds, was modified with S or R-γ⁴-bis(homo-phenylalanine) in positions 3 or 4, or both 3 and 4. These modifications changed the flexibility of new analogues and distribution of intramolecular hydrogen bonds. Analogues 11 c(Pro¹-Pro²-Phe³-S-γ⁴-hhPhe⁴-Leu⁵-Ile⁶-Ile⁷-Leu⁸-V...
Article
Full-text available
The varroa mite, Varroa destructor, is a devastating ectoparasite of the honey bees Apis mellifera and A. cerana. Control of these mites in beehives is a challenge in part due to the lack of toxic agents that are specific to mites and not to the host honey bee. In searching for a specific toxic target of varroa mites, we investigated two closely re...
Article
Rhodnius prolixus is a blood-gorging hemipteran that takes blood meals that are approximately 10 times its body weight. This blood meal is crucial for growth and development and is needed to ensure a successful molt into the next instar. Kinins are a multifunctional family of neuropeptides which have been shown to play a role in the control of feed...
Article
Cyclolinopeptide A, naturally occurring immunomodulatory nonapeptide, was modified with S or R-γ(3)-bis(homophenylalanine) in positions 3 or 4, or both 3 and 4. The replacement of one or both Phe residues by γ(3)-hhPhe led to decrease of their conformational flexibility in the analogues in comparison to CLA. All cyclic peptides, except 11, exist as...
Article
The CAP(2b) neuropeptide family plays an important role in the regulation of the processes of diuresis and/or antidiuresis in a variety of insects. While Manse-CAP(2b) (pELYAFPRV-NH(2)) and native CAP2bs elicit diuretic activity in a number of species of flies, native CAP2b sequences have been shown to elicit antidiuretic activity in the kissing bu...
Article
Full-text available
This paper presents the synthesis and solution conformational studies of the tripeptides Fmoc-Ala-(R)-(αMe)Ser(Ψ(H,H)Pro)-Ala-OBu(t) (6a) and Fmoc-Ala-(S)-(αMe)Ser(Ψ(H,H)Pro)-Ala-OBu(t) (6b). Additionally, the X-ray structure of 6a is given. NMR analysis corroborated by theoretical calculations (XPLOR) shows that in both peptides the amide bond bet...
Article
The pyrokinins (PK) are multifunctional neuropeptides found in a variety of arthropod species, including the pea aphid Acyrthosiphon pisum (Hemiptera: Aphidae). A series of biostable pyrokinin analogs based on the shared C-terminal pentapeptide core region were fed in solutions of artificial diet to the pea aphid over a period of three days and eva...
Article
Peptides j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / p e p t i d e s Biostable and PEG polymer-conjugated insect pyrokinin analogs demonstrate antifeedant activity and induce high mortality in the pea aphid Acyrthosiphon pisum (Hemiptera: Aphidae) a b s t r a c t The pyrokinins (PK) are multifunctional neuropepti...
Article
The multifunctional 'insect kinins' of arthropods share the evolutionarily conserved C-terminal pentapeptide core sequence Phe-X(1)-X(2)-Trp-Gly-NH(2), where X(1)=His, Asn, Ser, or Tyr and X(2)=Ser, Pro, or Ala. Insect kinins regulate diuresis in many species of insects, including the house cricket, Acheta domesticus. Insect kinins, however, are su...
Article
Full-text available
The dormant state known as diapause is widely exploited by insects to circumvent winter and other adverse seasons. For an insect to survive, feed, and reproduce at the appropriate time of year requires fine coordination of the timing of entry into and exit from diapause. One of the hormones that regulates diapause in moths is the 24-aa neuropeptide...
Article
High doses of chemotherapeutics in clinical treatment, leading to cell toxicity, can be lowered by co-administration of other immunoregulatory drugs. The aim of this study was to evaluate effects of several derivatives of cyclolinopeptide A (CLA), derived from linen seeds, on the suppressive action of metothrexate (MTX) in a mouse model of humoral...
Article
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Article
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Article
The pyrokinin/pheromone biosynthesis activating neuropeptide (PK/PBAN) family plays a significant role in the regulation of reproductive and developmental processes in a variety of insects. A transPro, type I beta-turn has been previously identified as important for the activity of PK/PBAN peptides. A PK/PBAN analog (PPK-Jo) incorporating a novel d...
Article
Full-text available
In the present study we describe the synthesis and some pharmacological properties of eight new analogues of bradykinin (BK). Two peptides were designed by substitution of position 7 or 8 of the known [D-Arg(0),Hyp(3),Thi(5,8),D-Phe(7)]BK antagonist (Stewart's antagonist) with L-pipecolic acid (L-Pip). The next two analogues were obtained by replac...
Article
The pyrokinin/pheromone biosynthesis activating neuropeptide (PK/PBAN) family plays a multifunctional role in an array of important physiological processes in a variety of insects. An active core analog containing an (E)-alkene, trans-Pro isosteric component was evaluated in four disparate PK/PBAN bioassays in four different insect species. These b...
Article
Immune response suppressors are used in the medical praxis to prevent graft rejection after organ transplantation and in the therapy of some autoimmune diseases. Cyclolinopeptide A, naturally existing immunomodulatory peptide, was modified with homophenylalanine in positions 3 (4), 4 (5) or both 3 and 4 (6). The conformational influence of the repl...
Article
The pyrokinin/pheromone biosynthesis activating neuropeptide (PK/PBAN) family plays a multifunctional role in an array of important physiological processes in insects, including regulation of sex pheromone biosynthesis in moths. A cyclic PK/PBAN analog (cyclo[NTSFTPRL]) retains significant activity on the pheromonotropic HevPBANR receptor from the...
Article
CLA, a natural, highly hydrophobic cyclic nonapeptide with sequence c(Pro(1)-Pro(2)-Phe(3)-Phe(4)-Leu(5)-Ile(6)-Ile(7)-Leu(8)-Val(9)-), isolated from linseed oil, was found to possess a strong immunosuppressive activity comparable, in low doses, with that of CsA, with a mechanism that depends on the inhibition of the interleukin-1 and interleukin-2...
Article
Spectroscopic data, including electronic absorption, CD and EPR results, as well as theoretical calculations have shown that the insertion of 4-aminopyroglutamate, a novel cis-peptide bond mimic, in the insect kinin peptide leads to an effective ligand towards Cu(II) ions at basic pH ranges. The 4-aminopyroglutamate motif induces a specific peptide...
Article
The structure of Z-Proψ[CN4]-Ala-OBzl has been determined by X-ray crystallographic techniques. The structure crystallizes in space group P21 with cell constants a = 22.176(3) Å, b = 6.141(1)Å, c = 8.275(1) Å, β= 98.31(1), and Z = 2. The structure has been refined to a residual of 0.038 for 2538 independent data. The amide bond between the prolyl a...
Article
Spectroscopic data, including electronic absorption, CD and EPR results, as well as theoretical calculations have shown that the insertion of 4-aminopyroglutamate, a novel cis-peptide bond mimic, in the insect kinin peptide leads to an effective ligand towards Cu(II) ions at basic pH ranges. The 4-aminopyroglutamate motif induces a specific peptide...
Article
Immune response suppressors are used in the medical praxis to prevent graft rejection after organ transplantation and in the therapy of some autoimmune diseases. As a continuation of our previous work searching for new, effective suppressors devoid of toxicity, we present the synthesis, conformational analysis, and biological activity of nonapeptid...
Article
The multifunctional 'insect kinins' share the evolutionarily conserved C-terminal pentapeptide motif Phe-X1-X2-Trp-Gly-NH2, where X1=His, Asn, Ser, or Tyr and X2=Ser, Pro, or Ala; and are associated with the regulation of diuresis in a variety of species of insects. We previously reported the functional expression of a southern cattle tick (Boophil...
Article
The present work is part of our studies aimed at clarifying the influence of steric constraints in the N-terminal part of arginine vasopressin (AVP) and its analogs on the pharmacological activity of the resulting peptides. We describe the synthesis of eight new analogs of AVP or [3-mercaptopropionic acid (Mpa)]AVP (dAVP) substituted at positions 2...
Article
The insect kinins are present in a wide variety of insects and function as potent diuretic peptides in flies. A C-terminal aldehyde insect kinin analog, Fmoc-RFFPWG-H (R-LK-CHO), demonstrates stimulation of Malpighian tubule fluid secretion in crickets, but shows inhibition of both in vitro and in vivo diuresis in the housefly. R-LK-CHO reduced the...
Article
The insect kinins are present in a wide variety of insects and function as potent diuretic peptides in flies. A C-terminal aldehyde insect kinin analog, Fmoc-RFFPWG-H (R-LK-CHO), demonstrates stimulation of Malpighian tubule fluid secretion in crickets, but shows inhibition of both in vitro and in vivo diuresis in the housefly. R-LK-CHO reduced the...
Article
Insect neuropeptides of the insect kinin class share a common C-terminal pentapeptide sequence F1X1²X2³W4G5-NH2 (X2³ = P, S, A) and regulate such critical physiological processes as water balance and digestive enzyme release. Analogs of the insect kinin class, in which the critical residues of F1, P3, and W4 were replaced with β3-amino acid or thei...
Article
Insect neuropeptides of the insect kinin class share a common C‐terminal pentapeptide sequence F ¹ X 1 ² X 2 ³ W ⁴ G ⁵ ‐NH 2 (X 2 ³ = P, S, A) and regulate such critical physiological processes as water balance and digestive enzyme release. Analogs of the insect kinin class, in which the critical residues of F ¹ , P ³ , and W ⁴ were replaced with β...
Article
The insect kinins are present in a wide variety of insects and function as potent diuretic peptides, though they are subject to rapid degradation by internal peptidases. Insect kinin analogs incorporating stereochemical variants of ( 2S,4S )‐4‐aminopyroglutamate (APy), a cis ‐peptide bond motif, demonstrate significant activity in a cricket diureti...
Article
Cyclolinopeptide A (CLA), a cyclic nonapeptide from linseed, possesses strong immunosuppressive and antimalarial activity along with the ability to inhibit cholate uptake into hepatocytes. The structure of the peptide was studied extensively in solution as well as in the solid state. It is postulated that both the Pro-Pro cis-amide bond and an 'edg...
Article
CD studies on tetrazole analogues of opioid peptides show that peptides sharing the same N-terminal sequence, H-TyrPsi[CN(4)]Gly-, give very large Cotton effects of the Tyr side chain in the near-UV region. CD spectra of five such peptides: H-TyrPsi[CN(4)]Gly-Gly-Phe-Leu-OH (I), H-TyrPsi[CN(4)]Gly-Phe-Pro-Gly-Pro-Ile-NH(2) (II), H-TyrPsi[CN(4)]Gly-...
Article
It is generally accepted that the conformation of the N-terminal part of neurohypophyseal hormones analogues is important for their pharmacological activity. In this work, we decided to investigate how the substitution of positions 2 and 3 with the ethylene-bridged dipeptide would alter the pharmacological properties of OT, [Mpa1]OT, and [Cpa1]OT (...
Article
Full-text available
The aim of the investigation was to establish the chelating ability of a new proctolin analogue of the sequence Arg-Tyr-LeuPsi[CN(4)]Ala-Thr towards copper(II) ions. The insertion of the tetrazole moiety into the peptide sequence has considerably changed the coordination ability of the ligand. Potentiometric and spectroscopic (UV-Vis, CD, EPR) resu...
Article
Full-text available
To examine the effect on biological activity of replacing D-Cys in the opioid peptide H-Tyr-c[D-Cys-Gly-Phe(pNO2)-D-Cys]-NH2 in position 2 or/and 5 with α-hydroxymethylcysteine (α-Hmc), three analogues were synthesized. These compounds exhibit agonist activity at both µ and δ receptors. However, the most active analogue, with (S)-α-Hmc residue in p...
Article
In continuation of our efforts to elucidate the role of positions 2 and 3 in arginine vasopressin (AVP) and its analogues, we designed and synthesized peptides modified in these positions with l-beta-homophenylalanine (beta-Hph). Two of them had just this single modification, the next two peptides are analogues of the V2 agonist, namely [3-mercapto...
Article
The present work is a part of our studies aimed at clarifying the influence of sterical constraints in N-terminal part of AVP analogues on the pharmacological activity of the resulting peptides. In this study we described the synthesis of four new analogues of AVP substituted at positions 2 and 3 or 3 and 4 with two diastereoisomers of 4-aminopyrog...
Article
Full-text available
The title compound, C27H39N3O9, is a key intermediate in the synthesis of novel β-turn mimetics based on electrophilic amination of enantiomerically pure (S)-pyroglutamic acid. The mol­ecule adopts an extended conformation which is not stabilized by either intra- or intermolecular hydrogen bonding. The pyrrolidine five-membered ring adopts an envel...
Article
The title compound, C27H39N3O 9, is a key intermediate in the synthesis of novel β-turn mimetics based on electrophilic animation of enantiomerically pure (S)-pyroglutamic acid. The molecule adopts an extended conformation which is not stabilized by either intra- or intermolecular hydrogen bonding. The pyrrolidine five-membered ring adopts an envel...
Article
The aliphatic amino diacid alpha-aminosuberic acid can function as an effective, stable mimic of the hydrolysis-susceptible Tyr(SO3H) group in sulfakinin neuropeptide analogs for both hindgut contractile activity in cockroach and food intake-inhibition activity in the desert locust. In the analog, the acidic sulfate group is replaced with an acidic...
Article
Linear and cyclic cyclolinopeptide A (CLA) analogues containing alpha-hydroxymethylleucine (HmL) in positions 1, 4, and 1&4, and alpha-hydroxymethylvaline (HmV) in position 5, were synthesized by the solid-phase peptide strategy and cyclized with the 1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide/1-hydroxy-7-azabenzotriazole (EDC/HOAt) reagent. The...
Article
The insect kinins are potent diuretic peptides that preferentially form a cis-Pro, type VI beta-turn. An insect kinin analog containing (2S,4S)-4-aminopyroglutamate, a novel cis-peptide bond, type VI beta-turn motif, demonstrates significant activity in the physiological range in a cricket diuretic assay. This is the first instance of a 4-aminopyro...
Article
Three linear and three cyclic analogs of cyclolinopeptide A, with phenylalanine residues in position 8 and/or 9 replaced by N-benzylglycine, were synthesized using the SPPS method and cyclization with TBTU reagent. The peptides were examined for their immunosuppressive activity in a lymphocyte proliferation test. In order to test the importance of...
Article
Complex formation between Cu(II) and three tetrazole analogues of opioid peptide – deltorphin I has been investigated. In potentiometric and spectroscopic (UV–Vis, CD and EPR) studies have been established the thermodynamic stability, speciation and structure of Cu(II) complexes with Tyr-<sub>D</sub> -Ala-Phe-Asp-Val-Val-Gly-NH<sub>2</sub> (L<sub>1...
Article
Complex formation between Cu(II) and three tetrazole analogues of opioid peptide – deltorphin I has been investigated. In potentiometric and spectroscopic (UV–Vis, CD and EPR) studies have been established the thermodynamic stability, speciation and structure of Cu(II) complexes with Tyr-d-Ala-Phe-Asp-Val-Val-Gly-NH2 (L1), Tyr-Ψ(CN4)-Gly-Phe-Asp-Va...
Article
Full-text available
A study of the effect of the tetrazole moiety, a cis -amide bond surrogate, on the Cu(II) coordinating properties of oligopeptides is reported. Insertion of the tetrazole moiety Ψ[CN<sub>4</sub>] into the peptide sequence of [D-Ala<sup>2</sup>]deltorphin I changes considerably the coordination ability of the peptide. Potentiometric and spectroscopi...
Article
Two new analogues of a previously designed bradykinin (BK) antagonist, d-Arg-Arg-Pro-Hyp-Gly-Thi-Ser-d-Phe-Thi-Arg, substituted in position 8 by N-benzylglycine and N-benzyl-l-alanine were designed, synthesized and bioassayed. The results show an impressive enhancement of B2 antagonistic potencies of both peptides in comparison with the model. In t...
Article
Full-text available
In order to evaluate the role and influence of the methionine residue on the biological activity of cyclolinopeptide B, an analogue with methionine residue in position 7 replaced by the amphiphilic (S)-alpha-hydroxymethylmethionine residue was synthesized. This peptide exhibits high immunosuppressive activity in the cellular, and to a lesser degree...
Article
Full-text available
Insect kinin analogues of the sequence Phe-Phe-psi[CN(4)]-Ala-Trp-Gly-NH(2) containing (L-Phe(2),L-Ala(3)) and (L-Phe(2),D-Ala(3)) stereochemical variants of the tetrazole moiety, a mimic of the type VI beta-turn, demonstrate significant agonist and partial antagonist activity, respectively, in a cricket diuretic bioassay. A comparison of the solut...
Article
The first reported examples of C-terminal aldehyde analogs of an insect neuropeptide are described. They are hexapeptide insect kinin analogs Boc-VFFPWG-H and Fmoc-RFFPWG-H. Activity observed for these modified analogs in an in vitro insect diuretic assay confirms that the C-terminal aldehyde group is tolerated by an insect kinin receptor. The two...
Article
The two diastereomeric tripeptides f-(S)-HmMet-Leu-Phe-OMe and f-(R)-HmMet-Leu-Phe-OMe, analogues of the prototypical chemoattractant f-Met-Leu-Phe-OH, were synthesized in solution by classical methods and fully characterized. A conformational study was performed in solution by 1H-NMR. Concomitantly, the two peptides were tested for their ability t...
Article
The first reported examples of C-terminal aldehyde analogs of an insect neuropeptide are described. They are hexapeptide insect kinin analogs Boc-VFFPWG-H and Fmoc-RFFPWG-H. Activity observed for these modified analogs in an in vitro insect diuretic assay confirms that the C-terminal aldehyde group is tolerated by an insect kinin receptor. The two...
Article
its endocrine receptor (TRH-R 1 ). Marshall and coworkers used the active analog approach to computer assisted drug design to predict an active conformation for the binding of TRH to TRH-R 1 . 4,5 In this work, two main conformational possibilities were proposed. Of these two possibilities, the more frequently populated conformation is illustrated...
Article
The synthesis and some pharmacological properties of five new analogues of arginine vasopressin (AVP) substituted with N-benzylglycine are described. All new peptides were tested for pressor and uterotonic activity. The results obtained imply that the structural change studied is in general incompatible with interaction of the analogues with V1A an...
Article
Linear and cyclic analogues of cyclolinopeptide A (CLA) with two dipeptide segments (Val(5)-Pro(6) and Pro(6)-Pro(7)) replaced by their tetrazole derivatives were synthesized by the SPPS technique and cyclized using TBTU (O-(benzotriazol-1-yl)-1,1,3,3-tetramethyluronium tetrafluoroborate) reagent. The conformational properties of the c(Leu(1)-Ile(2...
Article
The insect kinin neuropeptides have been implicated in the regulation of water balance, digestive organ contraction, and energy mobilization in a number of insect species. A previous solution conformation study of an active, restricted-conformation cyclic analog, identified two possible turn conformations as the likely active conformation adopted b...
Article
Musca kinin (Musdo-K; NTVVLGKKQRFHSWG-NH(2)) and N-terminal truncated analogs of 4-14 residues in length were assayed for diuretic and myotropic activity on housefly Malpighian tubules and hindgut, respectively. The pentapeptide was the minimum sequence required for biological activity, but it was > 5 orders of magnitude less potent than the intact...
Article
Thermodynamic and spectroscopic studies have shown that the insertion of alpha-hydroxylmethylserine (HmS) residues into the N-terminal peptide motif of human serum albumin results in a very powerful chelating agent for Cu2+ and Ni2+ ions. The insertion of two HmS residues results in the HmS-HmS-His-OH/NH2 sequence, which is the most effective chela...

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