Tóm tắt
Summary
The octapeptide Gly(Gly3,Ala3)Tyr was the most effective inhibitor of the fibroin-rabbit antifibroin precipitin reaction among the peptides tested that ranged in size from tetra- to octapeptides (40% inhibition at 5–18 μm/ml). The tetrapeptides were considerably less effective than Gly(Gly3,Ala3)Tyr although one of them, Gly(Gly,Ala)Tyr (20% inhibition at 18–20 μm/ml) has the same qualitative amino acid composition as the most effective octapeptide inhibitor. The dodecapeptide fraction was the most active of the peptides compared, giving 50% inhibition at 5–8 μm/ml. Removal of carboxyl-terminal tyrosine from the active octapeptides resulted in a halving of their effectiveness as inhibitors. The results indicate that, although tyrosine appears to account for a disproportionate part of the binding of peptide to antibody, a sizable segment (at least 8 to 12 residues) of the glycyl, alanyl chain is involved in specific combination.
