March 10, 1950
Dr. G. E. Burch
Department of Medicine
The Tulane University
1430 Tulane Avenue, New Orleans
I thank you for your letter of February 27. We would like very much to have more samples of sickle cell blood sent to us.
Dr. Wells is also going to write to you shortly about some special needs.
The sickle cell work continues to go along well. The amino acid analyses of sickle cell anemia hemoglobin and normal hemoglobin
have been completed now. They show that the amino acid residues with carboxylic or ammonium ion side chains are present in
the same amount in the two kinds of hemoglobin, but there seems to be slightly less leucine and more serine in sickle cell
anemia hemoglobin than in normal hemoglobin, and probably less valine and more threonine. This difference would not contribute
directly to the difference in charge, and I myself do not feel absolutely sure that it exists. Dr. Wells has also found that
sickle cell trait individuals contain a percentage of sickle cell anemia hemoglobin in their red cells carrying from 25% to
44%. He is continuing this investigation. We are very grateful to you for your assistance.
My wife and I are going to be in New Orleans next month. I think that we shall arrive (from Mobile) on Friday, April 7, and
stay until the morning of Tuesday, April 11. I am speaking before the local section of the American Chemical Society on Monday
night. Also, I am going up to Philadelphia for Sunday. I am not sure about the plane schedules, bit I shall go up either Saturday
afternoon or Sunday morning, and probably return Monday morning.