Active sites of turtle and duck low molecular weight antibody to 2′4′dinitrophenol

Abstract

Low mol. wt antibody directed to the dinitrophenol (DNP) grouping has been raised in both turtles and ducks by repeated challenge with DNP- Brucella abortus. Antibody was purified from the serum of both species by a combination of affinity chromatography and gel filtration. Purified antibody, upon interaction with hapten, induced a shift in the visible absorption spectra of the hapten suggestive of the participation of tryptophan in the active sites of the two antibody forms analyzed. Affinity labeling of the two antibody forms was effected with the hapten analog, meta nitrobenzene diazonium fluoroborate. Examination of the diazo spectra of the labeled antibody suggested the participation of tyrosine in the active site of both turtle and duck antibody and the participation of at least one other residue in the active site of the turtle antibody. Affinity label was shown to distribute in different ratios on the heavy and light chains of the two antibody forms. The studies indicate basic similarities between the active sites of antibodies derived from two lower vertebrate species and several previously characterized mammalian species.