Navegando por Palavras-chave "resin"

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    Comparative time-course study of aminoacyl- and dipeptidyl-resin hydrolysis
    (Sociedade Brasileira de Química, 1997-01-01) Jubilut, Guita Nicolaewsky [UNIFESP]; Marchetto, Reinaldo; Cilli, Eduardo Maffud [UNIFESP]; Oliveira, Eliandre [UNIFESP]; Miranda, Antonio [UNIFESP]; Tominaga, Mineko [UNIFESP]; Nakaie, Clovis Ryuichi [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade Estadual Paulista (UNESP)
    The classic hydrolysis procedure for quantification of resin-bound aminoacyl and peptidyl groups with 12 N HCl: propionic acid was reevaluated by studying the influence of the nature of the resin and the resin-bound group. Their stability during acid hydrolysis was dependent on the C-terminal amino acid, and the order of acid stability was Phe > Val > Gly. Otherwise, the dipeptides Ala-Gly, Ala-Val, and Ala-Phe displayed enhanced rates of hydrolysis of the resin if compared with their parent aminoacyl groups. Amongthe resins assayed, the order of acid stability was: benzhydrylamine-resin>p-methylbenzhydrylamine-resin ≅4-(oxymethyl)-phenylacetamidomethyl-resin > chloromethyl-copolymer of styrene-1%-divinylbenzene. Important for peptide synthesis method, the findings demonstrate that longer hydrolysis times than previously recommended in the literature (1 h at 130 °C and 15 min at 160 °C for peptides attached to the chloromethyl-copolymer of styrene-1%-divinylbenzene) are necessary for the quantitative acid-catalyzed cleavage of some resin-bound groups. The observed broad range of hydrolysis time varied from less than 1 h to about 100 h.
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    First purification of heparan sulfate disaccharides with an amine resin used as solid support for peptide synthesis
    (Elsevier B.V., 2000-01-03) Carvalho, RSH; Tersariol, ILS; Nader, H. B.; Nakaie, C. R.; Universidade Federal de São Paulo (UNIFESP)
    For the first time, highly substituted benzhydryramine-resin (BHAR), a solid support used only for the peptide synthesis method was assayed successfully as an anion exchanger resin for fractionation of (-2)-, (-3)- and (-4)-charged disaccharides. (C) 2000 Elsevier Science B.V. All rights reserved.
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    Importance of the solvation degree of peptide-resin beads for amine groups determination by the picric acid method
    (Sociedade Brasileira de Química, 2000-10-01) Cilli, Eduardo Maffud [UNIFESP]; Jubilut, Guita Nicolaewsky [UNIFESP]; Ribeiro, Suely C. F. [UNIFESP]; Oliveira, Eliandre [UNIFESP]; Nakaie, Clovis Ryuichi [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The classic and important picric acid method used in polymers biochemical and chemical fields of polymers for amine group quantification was chosen in this work as a model for evaluating the influence of the resin bead solvation during an analytical procedure. It was observed that this method, proposed almost three decades ago, failed to quantify amine groups of peptidyl-resin containing aggregating and polar sequence. This was due to inefficient solvation of resin beads when only CH2Cl2 was used for picrate anion binding and subsequent washing steps. It was demonstrated that the use of CH2Cl2/DMF (dimethylformamide) and CH2Cl2/EtOH solutions during these steps allows correct determination of peptidyl-resin amine groups. Besides the importance for the solid phase peptide synthesis methodology itself, these findings also represent the first quantitative demonstration of the relationship between solvation degree and the efficiency of a polymer-supported analytical method.
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    Novel Copoly(Styrene-Divinylbenzene)-Resins with Different Phenylmethylamine Groups for Use in Peptide Synthesis Method
    (Bentham Science Publ Ltd, 2015-01-01) Souza, Sinval Estevam Gregorio de [UNIFESP]; Malavolta, Luciana [UNIFESP]; Cilli, Eduardo Maffud [UNIFESP]; Schreier, Shirley [UNIFESP]; Jubilut, Guita Nicolaewsky [UNIFESP]; Nakaie, Clovis Ryuichi [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Santa Casa Sao Paulo Sch Med Sci; Unesp; Universidade de São Paulo (USP)
    Differently than the 4-methylbenzhydrylamine-resin (MBHAR) which contains a methyl group coupled to the phenylmethylamine-functionalized copoly(styrene-divinilbenzene) structure, alternative resins containing the electron-donating 4-tert-butyl-(BUBHAR) or the electron-withdrawing 2-chloro-(ClBHAR) and 2,4-chloro-(diClBHAR) groups were developed as potential supports for carboxamide peptide synthesis. Initially, a time-course investigation of HF cleavage reaction (0 degrees C) with these resins bearing the vasoconstrictor angiotensin II (AngII, DRVYIHPF) or its Gly(8)-AngII analogue revealed that the peptide-BUBHAR linkage is much more labile than those with ClBHAR or diClBHAR. HF cleavage times of near 2 h or longer than 24 h were needed for complete removal of peptide chains from these two classes of resin, respectively. By including MBHAR and benzhydrylamine-resins (BHAR) in this comparative study, the decreasing order of acid stability of the peptidyl-resin linkage was diClBHAR > ClBHAR > BHAR > MBHAR similar to BUBHAR. The same stability order was observed for the HCl/ propionic acid hydrolysis reaction (130 degrees C) with the Phe-or Gly-resins. These findings thus suggest that ClBHAR and diClBHAR are not appropriate for use in peptide synthesis. Nevertheless, these supports could still be tested as stationary phases for affinity chromatography. When placed into more apolar solvents, the beads of all of these resins exhibited a greater swelling (as measured by a microscope) or higher mobility of the polymer matrix (as measured with EPR experiments using spin-labeled beads). Moreover, under the latter approach, BUBHAR displayed a comparatively higher solvation degree than did MBHAR (in DCM, DMF and NMP), with slightly higher peptide synthesis yields as well.
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    Polystyrene-type resin used for peptide synthesis: application for anion-exchange and affinity chromatography
    (Elsevier B.V., 2005-03-25) Carvalho, RSH; Ianzer, D. A.; Malavolta, L.; Rodrigues, M. M.; Cilli, E. M.; Nakaie, C. R.; Universidade Federal de São Paulo (UNIFESP); UNESP
    This paper deals with an unusual application for a copolymer of styrene-1 % divinylbenzene bearing high amount of aminomethyl groups for anion-exchange and affinity chromatography. the so-called aminomethyl resin (AMR), to date only employed for peptide synthesis, swelled appreciably in water and was used successfully to purify negatively charged peptides. By correlating swelling degree of beads with pH of the media, it was possible to estimate that the AMR amino group pK(a) is approximately 5.5. in addition, the synthesized acetyl-(NANP)(3)-AMR succeeded in the affinity interaction with large antibody molecules related to malaria transmission and raised previously against this dodecapeptide sequence. (C) 2004 Elsevier B.V. All rights reserved.
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    Solvation of polymers as model for solvent effect investigation: proposition of a novel polarity scale
    (Elsevier B.V., 2002-05-27) Malavolta, L.; Oliveira, E.; Cilli, E. M.; Nakaie, C. R.; Universidade Federal de São Paulo (UNIFESP); Univ Barcelona
    A precise understanding of the polymer solvation effect has been considered crucial to many modem methods, but its dependence on the polarity of the medium is still not entirely established. To more thoroughly address this issue, the swelling degrees of polymers with a great variety of structures. taken as solute-models. were measured and correlated with the polarity of ca. 30 solvent systems. Relevant for any resin-supported methods, a characteristic solvation behavior of each class of polymeric material was detected. Moreover by interpreting the relationship between the large set of solute-solvent interaction data and the most solvent properties known so far, the sum of solvent electron acceptor (AN) and donor (DN) numbers, at a 1:1 proportion was suggested as an alternative and more accurate empirical solvent polarity scale. (C) 2002 Elsevier B.V. All rights reserved.
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    Study of the effect of the peptide loading and solvent system in SPPS by HRMAS-NMR
    (Wiley-Blackwell, 2005-09-01) Valente, A. P.; Almeida, FCL; Nakaie, C. R.; Schreier, S.; Crusca, E.; Cilli, E. M.; UNESP; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP); Universidade Federal do Rio de Janeiro (UFRJ)
    The SPPS methodology has continuously been investigated as a valuable model to monitor the solvation properties of polymeric materials. in this connection, the present work applied HRMAS-NMR spectroscopy to examine the dynamics of an aggregating peptide sequence attached to a resin core with varying peptide loading (up to 80%) and solvent system. Low and high substituted BHAR were used for assembling the VQAAIDYING sequence and some of its minor fragments. the HRMAS-NMR results were in agreement with the swelling of each resin, i.e. there was an improved resolution of resonance peaks in the better solvated conditions. Moreover, the peptide loading and the attached peptide sequence also affected the spectra. Strong peptide chain aggregation was observed mainly in highly peptide loaded resins when solvated in CDCl3. Conversely, due to the better swelling of these highly loaded resins in DMSO, improved NMR spectra were acquired in this polar aprotic solvent, thus enabling the detection of relevant sequence-dependent conformational alterations. the more prominent aggregation was displayed by the VQAAIDYING segment and not by any of its intermediary fragments and these findings were also corroborated by EPR studies of these peptide-resins labelled properly with an amino acid-type spin probe. Copyright (c) 2005 European Peptide Society and John Wiley & Sons, Ltd.
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    Use of commercial anion-exchange resins as solid support for peptide synthesis and affinity chromatography
    (Elsevier B.V., 2003-07-01) Nakaie, C. R.; Lanzer, D. A.; Malavolta, L.; Cilli, E. M.; Rodrigues, M. M.; Universidade Federal de São Paulo (UNIFESP); Univ Estadual Paulista
    This report demonstrates that due to the presence of residual reactive sites in their matrices, classical diethylaminoethyl-attaching commercial anion-exchanger resins such as DEAE-MacroPrep and DEAE-Sephadex A50 supports can be used for peptide synthesis. Moreover, due to the high stability of the peptide-resin bond in the final cleavage treatments, desired peptidyl-resins free of side-chain protecting groups, which enables them to be further used as solid support for affinity chromatography, can be obtained. To demonstrate this potentiality, a fragment corresponding to the antigenic and immunodominant epitope of sporozoites of the Plasmodium falciparum malaria parasite was synthesized in these traditional resins and antibody molecules generated against the peptide sequence were successfully retained in these peptidyl supports. Due to the maintenance of their original anion-exchange capacities, the present findings open the unique possibility of applying, simultaneously, dual anion-exchange and affinity procedures for purification of a variety of macromolecules. (C) 2003 Elsevier Science (USA). All rights reserved.
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    Use of the same polymer for synthesis and purification of peptides
    (Sociedade Brasileira de Química, 2005-04-01) Silva, Elias Horacio da [UNIFESP]; Etchegaray, Augusto [UNIFESP]; Carvalho, Regina S. H. [UNIFESP]; Jubilut, Guita Nicolaewsky [UNIFESP]; Miranda, Antonio [UNIFESP]; Nakaie, Clovis Ryuichi [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    This work reveals an uncommon but valuable biotechnological approach regarding the use of a same polymer (benzhydrylamine-resin, BHAR) for synthesis and anion exchange purification of peptides. Initially, the octapeptide DRVYIHPF-NH2 was synthesized in 1% and 3% cross-linked BHAR, attaching 2.5 mmol g-1 ammonium groups. Due certainly to its less rigid polymeric backbone, higher synthesis yield (about 80%) was achieved with the former resin. Next, the negatively charged peptides DEVYEHPF-NH2 and DEVYEDPF-NH2 (-1 and -3 in neutral pH, respectively), both synthesized in 1% BHAR were submitted to chromatographic separation test in this same type of resin (1% and 3%). Following comparative results of peptide synthesis and swelling data of resin beads obtained by microscopy, an improved separation of both peptides occurred with 1% BHAR batch. These findings demonstrated that BHAR applied so far for peptide synthesis, when containing high amount of positively charged ammonium groups, can be also used alternatively as a solid support for chromatographic purification of this type of biological molecule.
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    Uso da FTIR na obtenção de resinas e na síntese de peptídeos em fase sólida
    (Sociedade Brasileira de Química, 2011-01-01) Cespedes, Graziely Ferreira; Vicente, Eduardo Festozo; Cilli, Eduardo Maffud [UNIFESP]; Jubilut, Guita Nicolaewsky [UNIFESP]; Nakaie, Clovis Ryuichi [UNIFESP]; Universidade Estadual Paulista (UNESP); Universidade Federal de São Paulo (UNIFESP)
    Despite the increase in peptide chain aggregation, which decreases the rate of coupling reactions, the synthesis and use of very highly substituted resins still remains as a controversial point in the SPPS, due to its clear economical advantages (lesser solvent consumption and higher amount of peptide per synthesis). In order to better investigate the synthesis and the use of very highly substituted resins, the FTIR, NMR and EPR were compared. By FTIR techniques it was possible to follow all the steps of resin synthesis and the factors affecting the aggregation of the chains inside the peptidil-BHAR and MBHAR.