hemoglobin

As a noun hemoglobin

is the iron-containing substance in red blood cells that transports oxygen from the lungs to the rest of the body; it consists of a protein (globulin''), and ''haem (a porphyrin ring with an atom of iron at its centre).

As a verb desaturate is

(of a colour) to lessen saturation.

As nouns the difference between hemoglobin and sulfhemoglobin

is that hemoglobin is the iron-containing substance in red blood cells that transports oxygen from the lungs to the rest of the body; it consists of a protein (globulin), and haem (a porphyrin ring with an atom of iron at its centre) while sulfhemoglobin is any of a group of derivatives of hemoglobin, often in the presence of ferrihemoglobin, that are incapable of transporting oxygen.