Análise da utilização dos novos inibidores da trombina na prática médica

Blaya, Carolina; Prati, Clarissa; Boneti, Cristiano; Bonamigo, Daniela; Krumenauer, Rita Carolina Pozzer; Rosito, Guido A.

doi:10.1590/s0066-782x1998000800013

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References 26 publications

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“…PLfosfolipídeos. Fonte: Modificado de Blaya et al (1998) Além disso, a regulação alostérica permite que a trombina tenha dupla função nos processos de promoção e interrupção da coagulação através da ativação do sistema anticoagulante pela proteína C. A trombina existe em duas formas conformacionais: uma é estabilizada pelo íon de sódio e tem alta especificidade para converter fibrinogênio em fibrina e a outra forma conformacional, que predomina na ausência de sódio, tem baixa especificidade para a conversão de fibrinogênio, mas alta especificidade para ligar-se à trombomodulina e ativar a proteína C. Dessa forma, a trombina desempenha funções anti e pró-coagulantes (BORISSOFF et al, 2010;DI CERA et al, 1995;JAKUBOWSKI;OWEN, 1989;LEW;WEAVER, 2008).…”

Section: Figura 6 -Cascata Da Coagulaçãounclassified

Síntese e ensaio de análogos estruturais de prolina no estudo da interação com trombina.

Silva¹

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SILVA, R. N. Synthesis and assay of structural analogues of proline in the study of interaction with thrombin. 2013. 82 p. Dissertation (Masters thesis in Biotechnology) -Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, 2013. Thrombin is a serine peptidase that acts as the main agent of the coagulation cascade, with procoagulant properties as well as anticoagulant and antifibrinolytic properties. The activity of thrombin can be inhibited by the binding of inhibitors to its three domains: the active site and its two exosites. The challenge of this work was the use of unnatural amino acids that could be recognized by thrombin and confer hydrolysis resistance when inserted in a given peptide sequence, generating high-affinity inhibitors. Among the 20 natural L-amino acids encoded, proline is the unique amino acid able to confer conformational constraint to the peptide wherein is inserted, and is recognized as a site of hydrolysis by a highly specific subgroup of peptidases denominated prolylpeptidases. Synthetic routes were employed in the functional group attached to the carbon in position 4 of the pyrrolidinic ring of trans-4-hydroxy-L-proline to obtain four proline analogues containing amino and guanidino groups in this position with cis and trans spatial isomerism. Additionally, the 4-guanidino phenylalanine, known by possess characteristics of aromaticity and cationic character, was compared with the analogues of proline in all tests. These amino acids were employed in the synthesis of bivalirudin analogues. Among the thrombin inhibitors presently available on the market, bivalirudin is structurally characterized as an inhibitor of 20 amino acids that can be cleaved at Arg-Pro position and has elements that interact with the active site and exosite I, presenting an inhibition constant between 1.9 ─ 2,3 nM . For a preview check of the interaction between the analogues generated with the active site of thrombin, a computer simulation was performed by molecular docking with each analogue. Assays of competitive inhibition and platelet aggregation have demonstrated that the analogues present inhibitory activity and resistance to hydrolysis when incubated with human thrombin. Among the proline analogues synthesized, the peptide containing trans-4-guanidino-Lproline stood out from the others in competitive inhibition assays, with an inhibition constant of 168 nM. However, the synthesized peptide with the amino acid 4-guanidino-L-phenylalanine presented the highest inhibitory activity in comparison to proline analogues, with an inhibition constant of 6,2 nM. In future works, these analogues of bivalirudin may have the inhibitory effect improved through new changes in the functional groups attached to the proline analogues. Furthermore, modifications can be made to obtain non-peptide analogues in the development of thrombin inhibitors administered orally.

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Section: Figura 6 -Cascata Da Coagulaçãounclassified

Síntese e ensaio de análogos estruturais de prolina no estudo da interação com trombina.

Silva¹

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show abstract

Análise da utilização dos novos inibidores da trombina na prática médica

Cited by 1 publication

References 26 publications

Síntese e ensaio de análogos estruturais de prolina no estudo da interação com trombina.

Síntese e ensaio de análogos estruturais de prolina no estudo da interação com trombina.

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