Hemoglobin Subunits

[Pranav Kadiyala 1A]

I know that the myoglobin is a heme complex connected to a protein as well as an O2 on the iron. Is the protein it's connected to myoglobin, or is the entire molecule myoglobin? Additionally, hemoglobin as 4 subunits, and 4 Iron atoms total. Are each of these subunits a heme complex+attached protein, or just the attached protein?

[Brittney Nguyen 2L]

Hi!

I believe that myoglobin refers to the Fe + heme complex + amino acid histidine. Thus, I think that hemoglobin has 4 of these Fe + heme + amino acid structures.

Although, I might be wrong because I'm not exactly sure what protein you're talking about. Could you clarify?

[Isabella Chou 1A]

I agree with Brittney, I think myoglobin refers to the entire molecule, including the Heme complex and histidine. For hemoglobin, I think we just have to know that hemoglobin has four myoglobin-like molecules, but the structure of each subunit of hemoglobin is not entirely the same as myoglobin.

[rhettfarmer-3H]

I think the best way of thinking of this in this class. Is that the heme structure, the histine, and the oxygen make the complete complex of myoglobin. Therefore, it answer your question the protein is attached to the bottom of the Fe so it is part of the heme structure in a way. So the 4 NH3 and o2 and the protein make the coordination number of 6 for the iron molecule. For the sake of hemoglobin, it's just 4 of this myoglobin.