29701-41-5Relevant academic research and scientific papers
PEPTIDE SYNTHESIS CATALYZED BY NATIVE PROTEINASE K IN WATER-MISCIBLE ORGANIC SOLVENTS WITH LOW WATER CONTENT
Cerovsky, Vaclav,Martinek, Karel
, p. 2027 - 2041 (2007/10/02)
Rection of Ac-Tyr-OEt with HBr.Gly-NH2, catalysed by free proteinase K in various water-miscible organic solvents in the presence of triethylamine and 5 mol percent of water, was studied.Some aliphatic alcohols and acetonitrile proved to be suitable solvents.The effect of water content (2 percent - 20 percent) on the synthesis of Ac-Tyr-Gly-NH2 was studied using acetonitrile as solvent.Lowering of the water content to 5 percent or 2 percent led to almost 100 percent yield of the desired dipeptide; higher water content accelerated the reaction reducing at the same time the yield of Ac-Tyr-Gly-NH2 due to the concurrent hydrolysis of the ester Ac-Tyr-OEt.No reaction was observed in the absence of base (triethylamine), wereas an excess of base only retarded the reaction.The enzyme is capable of catalyzing the peptide bond synthesis with N-acylamino acids or N-acyl peptides as acylating components, which may contain all types of L-amino acid residues (except Pro) in the P1 position.However, the peptide bond synthesis depends strongly on the amino component composition, particularly on the amino acid residue in the P'1 position.Only amides of glycine and of hydrophillic amino acids were acylated with Ac-Tyr-OEt; amides of hydrophobic amino acids enter the reaction only reluctantly or not at al.The presence of Leu or Phe in position P'2 and Leu in position P'3 has not so negative effect on acylation of the amino component as has in presence in the P'1 position.The choice of protecting groups for the α-carboxyl of the amino component is restricted only to amide and in some cases its undesired enzymatic removal was observed.Unprotected peptides seem to be suitable amino components.
FREE CHYMOTRYPSIN-CATALYZED SYNTHESIS OF PEPTIDE BOND AN ALIPHATIC ALCOHOLS WITH LOW WATER CONTENT
Cerovsky, Vaclav,Martinek, Karel
, p. 266 - 276 (2007/10/02)
The effect of water content on free chymotrypsin-catalyzed reaction of Ac-Tyr-OEt with HBr*Gly-NH2 in triethylamine-containing 2-propanol was studied.Maximum yield of dipeptide Ac-Tyr-Gly-NH2 was obtained in 2-propanol with 2percent of water.Lower water content retards the reaction.Although higher water content accelerates the process, the yield of the dipeptide is reduced by enzymatically catalyzed hydrolysis of Ac-Tyr-OEt.The studied reaction proceeds analogously also in other aliphatic alcohols with low content of water except in methanol; it does not take place in dimethylformamide or dimethyl sulfoxide containing 2percent or 20percent of water.In 2-propanol with 2percent or 5percent of water, syntheses of the protected amino-terminal oxytocine and vasopressin tripeptide as well as other model peptides, were studied.In all the described experimetns, α-chymotrypsin without any stabilization or immobilization was employed.
