This is the hydrophobic structure of Hemoglobin. It has been procedurally shaded for a nice organic look. Its ready right out of the box to incorporate into any scientific visualization.
Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates and the tissues of some invertebrates. Hemoglobin in the blood is what transports oxygen from the lungs or gills to the rest of the body (i.e. the tissues) where it releases the oxygen for cell use, and collects carbon dioxide to bring it back to the lungs.
In mammals, the protein makes up about 97% of the red blood cells' dry content, and around 35% of the total content (including water). Hemoglobin has an oxygen binding capacity of 1.34 ml O2 per gram of hemoglobin, which increases the total blood oxygen capacity seventyfold compared to dissolved oxygen in blood. The mammalian hemoglobin molecule can bind (carry) up to four oxygen molecules.