Use of Ultraviolet Absorption Spectroscopy in the Quantitative Precipitin Reaction

Abstract

The effects of acid and alkali on several purified plasma proteins employed as antigens, and on their homologous specific precipitates, have been reported. The ultraviolet absorption properties of these antigens and their homologous rabbit antibodies have been shown to be largely dependent upon their tyrosine and tryptophane content. The ultraviolet absorption properties of the rabbit antibodies studied are very similar to those of human serum γ-globulin, and it is suggested that the tyrosine and tryptophane content of the rabbit antibodies is very similar to that of human serum γ-globulin. E^1%_1cm has been calculated for several rabbit antibodies. A method is described for using the spectrophotometer for studies of the quantitative precipitin reaction. The spectrophotometric method of determining total and antibody protein in specific precipitates has been applied to the study of the precipitation of several human and bovine plasma proteins by their homologous rabbit antisera.