To: Professor Pauling
From: Walt Schroeder
Subject: Number of Isoleucine Residues Per Molecule of Hemoglobin
In the paper which described the analysis of hemoglobins, we stated that the minimum molecular weight of both proteins must
be about 67,000 because there is only one isoleucine residue per molecule of thus weight but we did not comment further on
Recently, I have wondered whether we should not have called more attention to this fact because it does not show that in human
Hb any dissociation by urea or in very dilute solution must result in dissimilar fragments. Dr. Corey and I think that a
short to the JACS which stresses this result might be worthwhile.
However, in looking up literature for this note I have been unable to find any statement which suggests that hemoglobin might
disassociate into identical fragments of half or quarter molecular weight or that the molecule might contain four identical
peptide chains & coincide with the four hemes although both Dr. Corey and I fell that we have heard or read such statements.
Do you think that such a note would be advisable and are you aware of any published statements such as I have described?