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Master's Dissertation
DOI
10.11606/D.46.1985.tde-11112013-150530
Document
Author
Full name
Maria Teresa Machini
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 1985
Supervisor
Title in Portuguese
Termolisina como catalisador na síntese de DI- e tripeptídeos contendo asparagina
Keywords in Portuguese
Asparagina
Enzimas (Síntese)
Enzimas proteolíticas
Peptideos (Síntese)
Termolisina
Abstract in Portuguese
Com o objetivo de estudar a potencialidade do emprego de termolisina como catalisador nas reações de incorporação de N-acil-asparagina a ésteres de aminoácidos e peptídeos, foram sintetizados os seguintes di- e tripeptídeos: Boc-Asn-Ile-OBzl, Z-Asn-Ile-OBzl, Moz-Asn-Ile-OBzl, Boc-Asn-Leu- OBzl, Z-Asn-Leu-OBzl, Moz-Asn-Leu-OBzl, Z-Asn-Leu-OEt, Boc-Asn-Phe-OBzl, Z-Asn-Phe-OBzl, Moz-Asn-Phe-OBzl, Z-Asn-Phe- OEt, Z-Asn-Val-OBzl, Moz-Asp-Val-OBzl, Moz-Asn-Ile-Gly-OBzl, Moz-Asn-Ile-Ala-OBzl, Moz-Asn-Ile-Leu-OBzl e Moz-Asn- Ile-Phe-OBzl. Todos os peptídeos foram obtidos na forma pura, com bom rendimento e foram analisados e caracterizados por cromatografia em camada delgada, ponto de fusão, análise elementar, análise de aminoácidos e ressonância magnética protônica. Entre os grupos protetores de asparagina, benziloxicarbonil e p-metoxibenziloxicarbonil permitiram a obtenção dos dipeptídeos com excelentes rendimentos. Foi observado que os tripeptídeos requerem para a sua síntese menores concentração de enzima e tempo de reação em relação aos dipeptídeos. Não foi possível estabelecer a especificidade secundária da termolisina para o resíduo P'2 pois os rendimentos dos tripeptídeos sintetizados não apresentaram diferença significativa. Foi também realizado um estudo metodológico para determinar as condições ótimas de síntese de Boc-Asn-Ile-OBzl, que consistiu em analisar a influência do pH, concentração de enzima, concentraçao e volume da solução de acetato de sódio, proporção entre os componentes carboxílico e amínico, temperatura e adição de solvente orgânico ao meio de reação.
Title in English
Thermolysin as a catalyst in the synthesis of di-and tripeptides containing asparagine
Keywords in English
Asparagine
Enzymes (Synthese)
Peptides (Synthese)
Proteolytic enzymes
Thermolysin
Abstract in English
With de objective of studying the potential for the use of thermolysin as a catalyst in reactions of incorporation of N-acyl-asparagine into esters of aminoacids and peptides, the following di- and tripeptides were synthesized: Boc-Asn-Ile-OBzl, Z-Asn-Ile-OBzl, Moz-Asn-Ile-OBzl, Boc-Asn-Leu-OBzl, Z-Asn-Leu-OBzI, Moz-Asn-Leu-OBzl, Z-Asn-Leu-OEt, Boc-Asn-Phe-OBzl,Z-Asn-Phe-OBzl, Moz-Asn-Phe-OBzl, Z-Z-Asn-Phe-OEt, Z-Asn-Val-OEt, Moz-Asn-Val-OBzl, Moz-Asn-Ile-Gly-OBzl, Moz-Asn-Ile-Ala-OBzl, Moz-Asn-Ile-Leu-OBzl e Moz-Asn-Ile-Phe-OBzl. All of these peptides were obtained in pure form in good yield and analyzed and characterized by thin layer chromatography, melting point, elemental analysis, aminoacid analysis and proton magnetic resonance. Among the protecting groups of asparagine, benzyloxycarbonyl and p-methoxybenzyloxycarbonyl gave excellent yields of the dipeptides. Relative to the dipeptides, the synthesis of the tripeptides was found to require lower enzyme concentrations and temperatures. Since the yields of the tripeptides failed to exhibit significant differences, it was not possible to establish the existence of a secondary specificity of thermolysin for the residue P' 2 . A methodological study was also performed to determine the optimum conditions for synthesis of Boc-Asn-Ile-OBzl. This study consisted of an analysis of the influence of pH, enzyme concentration, concentration and volume of the solution of sodium acetate, relative proportions of the carboxyl and amino components, temperature, and addition of organic solvent to the reaction medium.
 
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Publishing Date
2014-05-15
 
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