Masayasu Kitagawa1, Yasuo Yagi1, David Pressman1
1Department of Biochemistry Research, Roswell Park Memorial Institute From the , 3 Buffalo, New York
Tóm tắt
Summary
Anti-Xp antibodies labeled with radioactive iodine were fractionated by adsorption on the Xp-adsorbent and subsequent successive elutions either with increasing concentrations of p-nitrobenzoate (fractions I, III and V) or with single concentrations of o-, m- and p-nitrobenzoates (fractions O, M and P).
Eluted antibodies were characterized by adsorption on three different immunoadsorbents containing the p-azobenzoate (Xp), p-azo-o-chlorobenzoate (o-ClXp) or p(p′-azophenylazo)-benzoate groups (X′) and elution at various concentrations of each of six haptens, benzoate, p-nitrobenzoate, m-nitrobenzoate, p-aminobenzoate, o-chlorobenzoate and o-nitrobenzoate. The effectiveness of each hapten to elute antibody from the adsorbent was expressed as the logarithm of the reciprocal of hapten concentration required to elute 50% of antibody adsorbed (pEC50).
The relative values of pEC50 between haptens differed from antibody fraction to antibody fraction, indicating that there is a difference of specificity among the antibody fractions. However, the order of pEC50 values of various haptens with each adsorbent was p-nitro- > m-nitro- > p-amino- = unsubstituted > o-chloro- > o-nitrobenzoates for all the antibody fractions as well as for the original unfractionated antibody.
The order of pEC50 values of various immunoadsorbents was X′ > o-ClXp > Xp for the original unfractionated antibody fraction and fraction III, V, M and P, X′ > o-ClXp = Xp for fraction I and X′ = o-ClXp = Xp for fraction O. This reflects the difference among the antibody fractions with respect to the abilities to accommodate the o-substituent group and with respect to the extent of the contribution of the protein portion surrounding the haptenic group to their combination with the immunoadsorbent.
