Question

Both myoglobin and globin (alpha, beta, gamma) have the capacity to bind oxygen, but the two are NOT interchangeable physiologically.

1.What are the two distinct functions that these proteins have?

2.What is the structural basis (specific features and mechanisms) of those distinct functions for the two proteins? Your answer must include appropriately labeled graphs of saturation curves. Be sure to also discuss specific structural features

Answer 1

Ans. 1 Distinct functions of myoglobin: It bounds to molecular oxygen and carries to the muscle tissues. The muscle cells utilises myoglobin during active respiration

Distinct functions of globin: It serves as a moeity for transporting oxygen to the entire body. The oxygen which is required for cellular metabolism has been provided by globin. Glodin collects the waste products such as the carbon dioxide from the body tissues.

Ans. 2 Structural basis of myoglobin: Myoglobin exists as a monomer and contains 8 right handed alpha helices. Each protein molecule posses one heme prosthetic group. Oxygen is bound directly to the iron atom of the prosthetic group.

Structural basis of globin: It is a tetrameric protein and binds 4 molecular oxygen on RBC's. It is composed of two alpha and two beta subunit of which alpha subunit posses 144 residues whereas beta subunit posses 146 residues.