Peptide, amino acid sequence methionine-containing

Alternatively, a probe for a gene can be prepared if part of the amino acid sequence of the protein encoded by the gene is known. A problem arises because a given peptide sequence can be encoded by a number of oligonucleotides (Figure 5.19). 1 hus, for this purpose, peptide sequences containing tryptophan and methionine are preferred, because these amino acids are specified by a single codon, whereas other amino acid residues have between two and six codons (see Table 4.4). 

The purpose for the 1998 study was to assess the ability of and determine the means whereby member facilities identify and solve problems in peptide synthesis 10 The potential for oxidation of amino acids such as methionine is always a concern for peptide chemists and biomedical researchers. A peptide mixture containing 70% correct peptide and 30% oxidized peptide was prepared and sent to member facilities to determine if the oxidized methionine would be detected (see Table 1). In addition to the oxidized peptide, a reverse synthesized peptide was sent to the participants. In previous studies, peptides had been submitted which had been synthesized in the reverse order and if only HPLC and mass spectrometric analyses was performed, the reverse synthesis would not be identified. Therefore, two peptides were designed with the second in the reverse order with two substitutions to equal the mass of the first peptide. These two peptides were readily separated by HPLC. The second peptide was sent to the laboratories, but the laboratories were given the first sequence and asked if the correct peptide had been made. Out of 20 participating laboratories ... 

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