General questions about Haemoglobin molecule

[vertex87]

I know that haemoglobin is the major component of red blood cells. What is the function of globin? and why does carbon monoxide form more stable bonds with the iron than oxygen molecule?

[biostudent84]

Hemoglobin (that's how we spell it in America =P) is one of my favorite proteins.

The word is a combination of the word Hemo, meaning "blood," and globin, meaning "glob" or "globe". The globular shape is one of the the Tertiary structures of proteins (Primary is chains, and Secondary is sheets). It is in a globe shape because it holds the iron ATOM (the iron is NOT chemically part of the hemoglobin) inside the protein.

The function of the iron atom is to chemically attract Oxyten and hold it inside the blood cell. This is why oxygenated blood is red...Iron Oxide is formed, and your blood is literally composed of rust. Consequently, in bugs, their hemoglobin has Copper, making their blood green.

As for the Carbon monoxide, I would need to draw pictures...something I can't do on this board. Your chemistry professor should be able to show you fairly easily.

Cheers!

Kyle

[vertex87]

Thank you for such an enlightening answer!! kk

[ERS]

Hemoglobin is an awesome molecule as Kyle mentioned! As an addendum though to some of his comments, "bugs" do not have hemoglobin but rather hemolymph--which is thier version of blood. Hemolymp is primarily water. The key thing is that bugs do not have circulating oxygen and so there is no need for a iron-type oxygen binder. Copper is in hemolymph as an ion, but does not carry oxygen (unless more recent research has shown otherwise). Rather the hemolymph serves to transport nutrients (carbs, fats, proteins, ions in solution etc..) to the various parts of the bug body. The kicker is that when you squish a bug and there is a big red splotch, you are most likely looking at pigment from their eyes and not bug blood.

Good answer Kyle!

[biostudent84]

I did not know that about the bug. Perhaps one of my former professors was wrong. It wouldn't be the first time.....

=/