42 



POLLARD: I haven't heard if he has. 



BUTTS: There is such a study going on at Reed College. 



POLLARD: We have radiated solid enzymes. There is no question in my 

 mind that dry material is completely different from wet and this I base largely 

 on the thermal inactivation of dry material. If you take a dry enzyme - - or a 

 dry virus -- they follow the ordinary reaction kinetics when you inactivate them 

 by heat. You get the ordinary monomolecular reaction, but the constants of the 

 process are totally different; apparently the entropy of activation is low. One 

 rather large source of entropy, breaking off water, is now no longer freely 

 available, and this seems to be universal. It is not specific in any way. It ap- 

 plies to anything dry. You can just categorically say that of dry material the 

 entropy of activation lies between 20 and minus 20 entropy units. I feel that you 

 have in this, admittedly in a somewhat indirect way, evidence that you have a 

 different material. There is an additional feature. If you have a small mole- 

 cule the vapor pressure at the surface of the small molecule is about 7 per cent 

 higher on account of the radius of curvature, just simply because of the surface; 

 therefore, even if you put a small molecule which is wet into practically saturat- 

 ed air, it will tend to dry as regards that kind of vapor. So the only sort of va- 

 por you can conceive of as being present in any material which is a high vac- 

 uum is presumably material vapor which is not vapor at all but which is bound, 

 and if it is bound, I should like to ask the question is water of crystallization 

 dry or wet? Is it bound by its hydrogen bond? That is the question. What I 

 was thinking about was this Franck mechanism that you were beating around two 

 years ago. 



BURTON: A moment ago somebody asked whether any of these dry amino 

 acids had been studied. Dr. Butts interjected the statement that some work 

 has been going on at Reed College. I think we ought to hear about that. 



BUTTS: I can tell you very generally what they have been getting. They 

 have irradiated a number of amino acids. Cystine and tyrosine were two that 

 gave very definite breakdown products, and, as I recall, serine was identified. 

 They irradiated a great many other substances, but those are the two that stick 

 in my mind particularly. It has been quite a while since I saw the report, but 

 they reported these were in the dry state. 



KAMEN: It is hard for me to see how you get serine from cystine. 



BUTTS: I believe alanine was also reported. 



GARRISON: Didn't they observe decarboxylation with that? 



BUTTS: I don't recall. 



GARRISON: It is my impression they did get decarboxylation. 



ALLEN: Did they find that in the presence of air? 



BUTTS: I don't know. 



KAMEN: Did these people in this research find something significant in the 

 fact that cystine is the most sensitive, or one of the most reactive, to radiation 

 under whatever conditions they had? 



BUTTS: Cystine is the one they found was the most sensitive to radiation. 



