. Basic mechanisms in radiobiology. monolayer and irradiated, then its antigenic property is lost or its ability to combine with antibodies is lost, but it is lost after consid- erably more radiation than will remove its solubility. Now, to start the discussion, I should like to suggest that we have an explanation for these events. This is largely aimed at Dr. Platzman. If we can get him started we have succeeded. We feel that two things occur. I rather like the method of approach that is used by Augenstine in the remarkable little book on "Information Theory In Biology", that Quastl
. Basic mechanisms in radiobiology. monolayer and irradiated, then its antigenic property is lost or its ability to combine with antibodies is lost, but it is lost after consid- erably more radiation than will remove its solubility. Now, to start the discussion, I should like to suggest that we have an explanation for these events. This is largely aimed at Dr. Platzman. If we can get him started we have succeeded. We feel that two things occur. I rather like the method of approach that is used by Augenstine in the remarkable little book on "Information Theory In Biology", that Quastler edited (University of Illinois Press, 1954). Augenstine analyzed protein denaturization in the following stages: 1. The breaking of a bond such as an S-S bond, which is a definite strong bond. This is associated with no entropy change and in- volves an energy change of about 20,000 calories per mole. 2. The breaking of a number of hydrogen bonds which opens the struc- ture. They have entropy associated with them, and each has a much smaller amount of actual energy, in the neighborhood of 6000 calo- ries per mole. 3. Another bond is joined, and, in Augenstine's approach, this is a newS-Sbond, not the right one for the original configuration. We should like to take almost exactly the same viewpoint for radiation action. Being a physicist, I know no chemistry and, therefore, I shall justdraw the whole structure. A physicist's idea of a protein backbone, with cross-linkages here and there is shown in Figure 1. I 1 I SUBSTRATE |. Cross linkage Figure 1. Schematic representation of events associated with the passage of a fast-charged particle through a protein molecule. What is said about protein obvi- ously can apply to nucleic acid also. Let us imagine that the particle tra- verses the molecule as shown in the dia- gram. This is the path of the fast- charged particle that does the ionizing. We will say that all it does is produce a primary ionization at A. As a result of the pri
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