Isolation of an Unpigmented Skin Reactive Constituent from Extracts of Ragweed Pollen by Electrophoresis. ∗

In 1938 experiments were undertaken, using a conventional moving boundary technique, to separate the fractions and to determine the electrical charge of the constituents of giant ragweed pollen extracts. At that time it was observed that the pigments in dialyzed ragweed extracts at pH 7.0 were negatively charged. The results during that summer and the succeeding winter, however, were contradictory, because the relation of the pigments to the biologically active constituents was uncertain.

Using the Tiselius 1 cell for the study of the moving boundaries of protein solutions and the Philpot-Svensson 2 technic to analyze the quantity and nature of the constituents, further progress may now be reported. Figures la and 1 b are illustrations of the type of curves given by the major constituent. This major constituent is negatively charged, slow moving, unpigmented, and highly skin reactive in persons sensitive to ragweed. A minor constituent, about 1/5 that of the unpigmented major constituent, appearing in the pigment moves approximately 10 times as fast as the unpigmented major one in Fig. la. The pigments apparently did not all migrate with the minor boundary but also moved towards the positive pole. Fig. lb, which also illustrates as a major constituent an unpigmented component has, in addition, several minor constituents migrating towards the positive pole. The electric mobility of the unpigmented skin reactive constituent is 0.05 μ/sec at 1.5° C. It is of interest to note that the electrical mobility of quartz particles in similar ragweed solutions studied by Abramson, Sookne and Moyer 3 approximately agrees with this value when temperature corrections for viscosity are made.

In Fig. 2, the section of the electrophoresis cell labelled (a) shows a Schlierung pattern of the boundary between the unpigmented slow moving active constituent and the buffer; section (b) shows a lightly pigmented section; section (c) was so highly pigmented that practically no light came through and section (d) contained the advancing column of pigmented constituents and shows many bands with electrical mobilities closely related to one another but with very low concentrations of each. These bands are essentially similar to those illustrated in Fig. lb.