lecture 15 biochem

What is the structure of myoglobin?

Monomeric protein with a single polypeptide chain.

Describe the oxygen-binding curve of myoglobin.

It follows a hyperbolic curve, indicating non-cooperative binding.

How many heme groups are present in hemoglobin?

Hemoglobin contains four heme groups, one in each subunit.

What is the primary function of myoglobin?

Primarily stores oxygen in muscle tissues.

Define the Bohr Effect in the context of hemoglobin.

Refers to how binding of H+ and CO2 inversely affects the binding of O2.

What triggers the conformational change from T state to R state in hemoglobin?

O2 binding triggers this structural change.

What is the significance of the Kd value for myoglobin?

Kd is referred to as p50, the O2 pressure at which myoglobin is 50% saturated.

How does 2,3-bisphosphoglycerate (BPG) affect hemoglobin's affinity for oxygen?

BPG decreases hemoglobin's affinity for oxygen by stabilizing the T state.

What type of curve does hemoglobin's oxygen-binding exhibit?

A sigmoidal curve, which indicates cooperative binding.

Why is the binding of carbon monoxide (CO) to hemoglobin hazardous?

CO has a much higher affinity for hemoglobin than O2, which reduces O2 transport.

What is myoglobin's oxygen-binding affinity compared to hemoglobin?

Myoglobin has a higher oxygen-binding affinity than hemoglobin, as it primarily functions to store oxygen rather than transport it.

In which tissues is myoglobin predominantly found?

Myoglobin is predominantly found in muscle tissues.

What physiological condition can increase the expression of myoglobin?

Physical training or hypoxia can increase the expression of myoglobin in muscles.

How many subunits are present in hemoglobin?

Hemoglobin consists of four subunits, specifically two alpha and two beta chains.

What role does iron play in myoglobin and hemoglobin?

Iron in the heme group of both proteins is crucial for oxygen binding.