A Stierandová | PubMed Health

PubMed1994

Sequence-dependent modification of Trp by the Pmc protecting group of Arg during TFA deprotection.

The extent of transfer of the Pmc protecting group from the guanidino group of arginine to the side chain of tryptophan depends on the spacial distance of these side chains. When these two amino acids are separated by one amino acid, the transfer of the Pmc protecting group is the most pronounced, and it cannot be completely prevented by the use of currently utilized scavenger mixtures. The extent of this side reaction also depends on the amino acid separating the arginine and tryptophan residues and position of tryptophan within the peptide chain as well as on the type of the solid-phase carrier.

Amino Acid Sequence↗

PubMedDate not supplied

Peptide-encoding for structure determination of nonsequenceable polymers within libraries synthesized and tested on solid-phase supports.

A method of indirectly determining the structure of nonpeptidic or nonsequenceable compounds that have been synthesized on individual particles of solid support is described. The technique permits the parallel synthesis of a compound that is not susceptible to Edman degradation (e.g., N-terminal-blocked peptide), or one containing components that cannot be identified by amino acid sequencing, together with a corresponding "coding" peptide. Each coupling step in the assembly of the nonsequenceable compound is followed by the coupling of an amino acid to a different attachment site of the same carrier particle, whereby the amino acid unambiguously codes for the previously coupled building block of the nonsequenceable compound. The rationale is to enable the sequence determination of a biologically active compound that has been identified through the screening of a library of nonequenceable compounds, by translating the sequence of its "coding" peptide, determined by Edman degradation, into the structure of the active compound. The technique facilitates the construction and screening of nonpeptidic libraries for the discovery of important pharmaceutical compounds.

Amino Acid Sequence↗