New approaches to peptide synthesis with the help of trypsin.

Picolyl esters of amino acids are suitable inverse substrates for trypsin. These esters can be used for peptide synthesis catalyzed by trypsin. Study of hydrolysis of non-specific substrates for trypsin permits to conclude, that hydrogen band in P'2 subsite is very important for their reactivity.

Thio-alpha-amino acids (S-acids) as a carboxyl component in peptide synthesis catalysed by papain.

Peptide synthesis catalysed by papain was studied using thio-alpha-amino acids (S-acids) as a carboxyl component. It was found, for example, that with Z-AlaSH (pK 2.70) the maximal yield of the peptide Z-AlaValNH2 was obtained at pH 8-8.

Synthesis and kinetic characterisation of omega-guanidinocarbonic acid ethyl esters as trypsin substrates.

Aliphatic omega-guanidinocarbonic acid ethyl esters of different chain length (C3-C6) were synthesized and characterized as 4-toluenesulfonates. The kinetic parameters of the trypsin-catalyzed hydrolysis indicate that the ethyl ester of delta-guanidinovaleric acid is the most effective substrate in this series. The Km value of this compound is in the same order of magnitude as those of arginine-containing ester substrates like N alpha-benzoylarginine ethyl ester (BAEE).

[Dipentafluorophenyl carbonate--a reagent for peptide synthesis].

Dipentafluorophenylcarbonate, belonging to transesterifiying reagents, has been prepared and used for the synthesis of pentafluorophenyl esters of amino acids. In contrast to many other reagents of the kind, its preparation is simple, it is highly reactive and at the same time stable upon storage.

Peptide synthesis catalyzed by papain at alkaline pH values.

The synthesis of peptides in the presence of papain at pH 8-9.5 is described. Starting substances are acylamino acid alkyl esters (the carboxyl component) and amides or tert.