I've just received a reprint from Fred Karush which is very pertinent to the discussion we had at lunch the other day.
Fred has done this experiment of reversable [sic] denaturation by the use of high concentrations of urea. While he won't
immediately admit this it seems to me that his finding that reversable [sic] denaturation can result in a virtual complete
restoration of antibody activity strongly supports the idea of differentiation of antibodies on the basis of amino acid sequence.
I am enclosing a thermofax of the relevant page or two which is taken from something called "Serological and Biochemical
Comparison of Proteins--14th Annual Protein Conference". I would be very pleased to have you reactions on this.
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First, heartiest congratulations for your well-deserved honor.
The experiments of Karush, while interesting, are not too conclusive of a refolding to a former antibody site structure.
Although urea will induce marked structural changes in the secondary structure of the protein, these may have nothing to do
with antibody finding activity changes noted. I'm wondering whether similar effects would not be manifested by equal
osmotic concentrations of other reagents like NaCl[?],
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amino acids, sugars, etc. which would not severely affect the secondary structure in a degree similar to that occassioned
[sic] by urea.
"An interesting experiment but one capable of variable interpretation". I'd be happy to discuss this further
with you sometime.