反应详情

The oligopeptides prepared as described in Example 2 were individually dissolved in PSA digestion buffer (12 mM tris(hydroxymethyl)-aminomethane pH8.0, 25 mM NaCl, 0.5 mM CaCl2) and the solution added to PSA at a molar ration of 100 to 1. Alternatively, the PSA digestion buffer utilized is 50 mM tris(hydroxymethyl)-aminomethane pH7.4, 140 mM NaCl. The reaction is quenched after various reaction times by the addition of trifluoroacetic acid (TFA) to a final 1% (volume/volume). Alternatively the reaction is quenched with 10 nM ZnCl2. The quenched reaction was analyzed by HPLC on a reversed-phase C18 column using an aqueous 0.1% TFA/acetonitrile gradient. The results of the assessment are shown in FIG. 2. Other oligopeptides prepared as described in Example 2 were tested in the same assay wherein the reaction was quenched at 4 hours. Those results of the assessment are shown in FIG. 3. The removal of an asparagine residue from the amino terminus of the oligopeptide results in a significant loss of PSA mediated peptide hydrolysis, while the presence of a glutamic acid residue at the carboxyl end of the peptide appears not to be essential to recognition by PSA.

1. customThe reaction is quenched
2. customafter various reaction times
3. customAlternatively the reaction is quenched with 10 nM ZnCl2
4. customThe quenched reaction
5. customThe results of the assessment
6. customwas quenched at 4 hours
7. customThose results of the assessment
8. customThe removal of an asparagine residue from the amino terminus of the oligopeptide