This decrease in redness is due to a disproportionate reduction of red cell hemoglobin (the pigment that imparts the red color) in proportion to the volume of the cell.

Sickle cell hemoglobin, however, after giving up oxygen, cling together and make the red blood cell stiff.

Itano also found that the globin portion of sickle cell hemoglobin had a barely detectable difference in electrical charge.

Pauling was convinced that sickle cell disease was caused by defective hemoglobin, and set Itano to find out what made sickle cell hemoglobin chemically different.

He found that, under certain conditions, sickle cell hemoglobin is positively charged while normal hemoglobin is not, creating a difference in electrophoretic mobility.

Now, she said, "someone has to look at sickle cell hemoglobin to see if what they found at Duke with normal hemoglobin applies."

Hemoglobin A (HbA) or adult hemoglobin is the most common human hemoglobin tetramer, comprising over 97% of the total red cell hemoglobin.

Chakrabarti also is working on fiber formation in sickle cell hemoglobin, the mutant form of hemoglobin responsible for sickle cell anemia.

The mean corpuscular hemoglobin, or "mean cell hemoglobin" (MCH), is the average mass of hemoglobin per red blood cell in a sample of blood.

A positive test result occurs when the haptoglobin binding capacity of the blood is saturated, leading to heme released from cell free hemoglobin to bind to albumin.