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  • 1
    Electronic Resource
    Electronic Resource
    Versuche zur Anwendung von Thermitase als Katalysator zur Knüpfung der Peptidbindung (1981)
    Springer
    Monatshefte für Chemie 112 (1981), S. 1099-1102 
    Details
    ISSN: 1434-4475
    Keywords: Enzymatic peptide synthesis ; Thermitase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The utility of thermitase, a thermophilic proteolytic enzyme fromThermoactinomyces vulgaris, as a catalyst for peptide synthesis has been studied using several Nα-benzyloxycarbonyl dipeptide esters as carboxyl components and Leu-NH2 as nucleophile. Couplings were most successful with substrates containing Met, Leu, Ala, Phe, Tyr in P1-position, and Val, Ala, Pro in P2, whereas the substrates with Val, Ile, Pro in P1 failed to couple.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00905078
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  • 2
    Electronic Resource
    Electronic Resource
    Model studies on the utility of nucleophiles bound to insoluble supports for enzymatic peptide synthesis (1982)
    Springer
    Monatshefte für Chemie 113 (1982), S. 331-337 
    Details
    ISSN: 1434-4475
    Keywords: α-Chymotrypsin ; Enzymatic peptide synthesis ; Papain ; Solidphase peptide synthesis ; Thermolysin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Thermolysin, α-Chymotrypsin und Papain wurden als Biokatalysatoren für die Kupplung verschiedener Carboxylkomponenten an kieselgel-gebundenes Leucinamid als Nucleophil eingesetzt. Für erfolgreiche Kupplungen war eine Spacerlänge von 21 kovalenten Bindungen entsprechend 7 Aminosäureresten erforderlich. Diese Synthesevariante eröffnet die Möglichkeit, racemisierungsfreie Segmentkondensationen an unlöslichen polymeren Trägern mit Hilfe von Proteasen durchzuführen.
    Notes: Abstract Thermolysin, α-chymotrypsin, and papain were used as biocatalysts for the coupling of several carboxyl components to silica-supported leucine amide as a nucleophile. A spacer length of 21 covalent bonds corresponding to 7 amino acid residues was required for successful coupling. This approach offers the possibility of using proteases for racemization-free segment condensations on insoluble polymeric supports.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00799560
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  • 3
    Electronic Resource
    Electronic Resource
    Modelluntersuchungen zur pepsinkatalysierten Peptidsynthese im wäßrig-organischen Zweiphasensystem (1983)
    Springer
    Monatshefte für Chemie 114 (1983), S. 571-579 
    Details
    ISSN: 1434-4475
    Keywords: Enzymic synthesis in biphasic systems ; Pepsin-catalyzed peptide bond formation ; Peptide synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The usefulness of biphasic aqueous-organic solvent systems for pepsin-catalyzed synthesis of model peptidesZ-X-Phe-Phe-OMe (X=Ala, Gln, Leu) has been demonstrated by coupling the correspondingZ-X-Phe-OH with H-Phe-OMe. The influence of various organic solvents on pepsin activity was examined. Some examples are given for the influence of nucleophile and enzyme concentration, bufferpH and organic solvent portion on product yield. Tetrachloromethane and mixtures of ethyl acetate/n-hexane proved to be especially useful allowing syntheses in good yields and within comparatively short reaction times of 2–6 hours.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00798612
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  • 4
    Electronic Resource
    Electronic Resource
    Model studies on carboxypeptidase Y catalyzed peptide synthesis in an aqueous-organic two-phase system (1983)
    Springer
    Monatshefte für Chemie 114 (1983), S. 343-347 
    Details
    ISSN: 1434-4475
    Keywords: Carboxypeptidase Y catalyzed peptide bond formation ; Enzymic synthesis in biphasic systems ; Peptide synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Carboxypeptidase Y katalysiert in einem Zweiphasensystem aus Tetrachlormethan und Carbonatpuffer die Reaktion vonZ-Phe-OMe und verschiedenenZ- undBoc-geschützten Dipeptidmethylestern mit Val-NH2 bzw. Leu-NH2. Nach diesem Verfahren werden die entsprechenden N-geschützen Tripeptidamide in präparativem Maßstab hergestellt. Bei einem Substrat-Nucleophil-Verhältnis von nur 1:2 oder 1:3 erhält man die Peptidderivate in Ausbeuten von 56–97%.
    Notes: Abstract Carboxypeptidase Y catalyzes in a biphasic system containing carbon tetrachloride and carbonate buffer the reaction ofZ-Phe-OMe and variousZ-andBoc-protected dipeptide methyl esters with Val-NH2 and Leu-NH2, respectively. This method has been applied to the synthesis of the corresponding N-protected tripeptide amides on a preparative scale. Using a substrate—nucleophile ratio of only 1:2 or 1:3 the peptide derivatives are obtained in yields of 56–97%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00798957
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  • 5
    Electronic Resource
    Electronic Resource
    Solubilisierende Schutzgruppen für enzymatische Peptidsynthesen Untersuchungen mit Polyoxyethylen-gebundenen Substraten (1985)
    Springer
    Monatshefte für Chemie 116 (1985), S. 111-117 
    Details
    ISSN: 1434-4475
    Keywords: Chymotrypsin ; Enzymatic peptide synthesis ; Liquid phase peptide synthesis ; Solubilizing protective groups ; Polyoxyethylene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The utility of amino acids and dipeptides esterified to solubilizing polyoxyethylene supports as substrates for protease-mediated peptide bond formation was studied using free and immobilized α-chymotrypsin as a catalyst. Poor yields were obtained with Nα-protected amino acid or dipeptide polyoxyethylene esters as carboxyl components, most probably due to a shielding of the active site of the acyl enzyme intermediate by the polymer favouring hydrolytic cleavage. Experiments with polyoxyethylene esters as nucleophiles gave good results with free chymotrypsin, immobilized chymotrypsin predominantly caused hydrolysis of the ester carboxyl component due to unfavourable interactions between the soluble and insoluble polymers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00798284
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  • 6
    Electronic Resource
    Electronic Resource
    Studies on enzymatic peptide synthesis in biphasic aqueous-organic systems with product extraction (1987)
    Springer
    Monatshefte für Chemie 118 (1987), S. 1279-1288 
    Details
    ISSN: 1434-4475
    Keywords: Enzymatic synthesis in biphasic systems ; Peptide synthesis ; α-Chymotrypsin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Die DipeptidderivateZ-Tyr-Leu-NH2 undMca-Tyr-Leu-NH2 wurden durch α-chymotrypsin-katalysierte Kupplung in biphasischen Systemen aus Puffer und Essigsäureethylester hergestellt. Im Vergleich zu einem rein wäßrigen Medium, in dem nahezu keine Synthese erfolgt, wird in einem biphasischen System die Synthesereaktion durch Extraktion des Dipeptids in die organische Phase wesentlich begünstigt. Es wurde der Einfluß verschiedener Reaktionsparameter, wie Pufferkonzentration, Reaktionszeit, Volumenverhältnis von organischer zu wäßriger Phase und Reaktandenkonzentration auf die Ausbeute anZ-Tyr-Leu-NH2 untersucht. Ein Austausch der hydrophobenZ-Gruppe gegen die hydrophilere Chloracetylgruppe führte zu besseren Dipeptidausbeuten bei höheren Reaktionsgeschwindigkeiten.
    Notes: Abstract The dipeptide derivativesZ-Tyr-Leu-NH2 andMca-Tyr-Leu-NH2 were synthesized by α-chymotrypsin-catalyzed coupling reactions in solvent systems consisting of buffer and ethyl acetate. In comparison to a pure aqueous medium, in which only insignificant synthesis takes place, the product formation is greatly enhanced in a biphasic medium due to extraction of the dipeptide into the organic phase. The influence of several reaction parameters, such as buffer concentration, reaction time, volume ratio of organic and aqueous phase, and reagent concentration on the yield ofZ-Tyr-Leu-NH2 was investigated. Replacement of the hydrophobicZ-group by the more hydrophilic chloroacetyl group resulted in better dipeptide yields at higher reaction rates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00816870
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  • 7
    Electronic Resource
    Electronic Resource
    Papainkatalysierte kinetisch kontrollierte Peptidsynthese. Verwendung von Alkylestern des Arginins als Aminokomponente (1989)
    Springer
    Monatshefte für Chemie 120 (1989), S. 437-443 
    Details
    ISSN: 1434-4475
    Keywords: Enzymatic peptide synthesis ; Arginine peptides ; Papain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The papain-catalyzed reaction of esters of Z-alanine with various arginine esters was investigated. Using H-Arg-OPr i as a nucleophile the expected dipeptide product results in high yield. Otherwise, reactions with arginine esters of primary alkohols provide products undergoing further reactions. This allows the synthesis of N-protected peptide esters containing two or more arginine residues in a one-step reaction. The influence of reaction conditions on the process was investigated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00811555
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  • 8
    Electronic Resource
    Electronic Resource
    On the use of carboxamidomethyl esters in the protease-catalyzed peptide synthesis (1986)
    Springer
    Monatshefte für Chemie 117 (1986), S. 1195-1204 
    Details
    ISSN: 1434-4475
    Keywords: Carboxamidomethyl ester as C-protecting group ; Enzymatic deprotection ; Peptide synthesis ; α-Chymotrypsin- and Papain-catalyzed peptide bond formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Es wurden die Carboxamidomethylester (CAM-Ester) vonZ- undBoc-geschütztem Alanin und Phenylalanin hergestellt mit dem Ziel, ihre Eignung als Substrate für α-chymotrypsin- und papainkatalysierte Hydrolyse- sowie Peptidsynthesereaktionen zu untersuchen. Die leichte, unter milden Bedingungen und in Abhängigkeit von der Enzymspezifität erfolgende Abspaltung derCAM-C-Schutzgruppe wurde nachgewiesen. An Beispielen wird die proteasekatalysierte Synthese verschiedener Peptidderivate unter Verwendung vonCAM-Estern als C-und N-Komponenten in wäßrig-organischen Medien belegt. Die für die Umsetzungen benötigten Reaktionszeiten sind vergleichsweise gering.
    Notes: Abstract Carboxamidomethyl esters (CAM esters) ofZ- andBoc-protected alanine and phenylalanine were prepared in order to investigate their usefulness as substrates for α-chymotrypsin- and papain-catalyzed hydrolysis and peptide synthesis reactions. The easy removal of theCAM-C-protecting group under mild conditions and dependent on the enzyme specificity was demonstrated. Examples are given for the protease-catalyzed synthesis of various peptide derivatives usingCAM esters as C- and N-components in aqueous-organic media. Comparatively short reaction times were observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00811332
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  • 9
    Electronic Resource
    Electronic Resource
    Model studies on protease-catalysed peptide synthesis using 9-fluorenylmethoxycarbonyl protected amino acid derivatives (1992)
    Springer
    Monatshefte für Chemie 123 (1992), S. 1015-1022 
    Details
    ISSN: 1434-4475
    Keywords: Enzymatic peptide synthesis ; Fmoc-protected amino acid derivatives ; Chymotrypsin ; Papain ; Thermolysin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Fmoc-Phe-OMe,Fmoc-Ala-OMe undFmoc-Gly-OH wurden unter katalytischer Wirkung von Chymotrypsin, Papain bzw. Thermolysin mit H-Leu-NH2 gekuppelt und der Einfluß verschiedener Reaktionsmedien und -parameter, wie Reaktanden- und Enzymkonzentration sowie Reaktionszeit, auf die Peptidbindungsbildung untersucht.
    Notes: Summary Fmoc-Phe-OMe,Fmoc-Ala-OMe andFmoc-Gly-OH were coupled with H-Leu-NH2 under catalytic action of chymotrypsin, papain and thermolysin, respectively. The influence of different reaction media and several reaction parameters, such as reactants and enzyme concentrations as well as reaction time, on the peptide bond formation was investigated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00810932
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  • 10
    Electronic Resource
    Electronic Resource
    Modelluntersuchungen zur papainkatalysierten Peptidsynthese im wäßrig-organischen Zweiphasensystem (1981)
    Springer
    Monatshefte für Chemie 112 (1981), S. 1165-1173 
    Details
    ISSN: 1434-4475
    Keywords: Enzymic synthesis in biphasic systems ; Papain-catalyzed peptide bond formation ; Peptide synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Several model peptides have been synthesized enzymatically using papain as a catalyst in biphasic aqueous-organic systems. The effect of different cosolvents,pH, buffer concentration, and reaction time on the papaincatalyzed synthesis was examined. A comparison of the results obtained indicates that water-immiscible organic solvents provide higher yields than methanol in papain mediated peptide synthesis with carboxyl components in the carboxyl free form. Furthermore, it could be established that papaincatalyzed peptide synthesis can be considerably speeded up by employing acyl peptide esters instead of acyl peptides. The former should promote the rapid formation of the acyl-enzyme intermediate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00905471
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