Hemoglobin and Myoglobin Overview

These flashcards cover key concepts related to the structure, function, and physiological roles of hemoglobin and myoglobin, focusing on their interactions with ligands, allostery, and the differences between adult and fetal hemoglobin.

What are negative allosteric effectors of hemoglobin?

Protons (H+), Carbon dioxide (CO2), and 2,3-BPG.

How many ligands can iron bind to in oxygen transport?

Iron can bind to 4 or 6 ligands depending on the environment.

What is the significance of α1β2 and α2β1 in hemoglobin?

They are responsible for subunit packing.

Why does myoglobin not exhibit changes to K₀.₅ in the presence of CO₂, protons, or BPG?

Because it has no histidine residues that would affect its affinity.

What is myoglobin with Fe3+ called?

Metmyoglobin.

What happens to K₀.₅ when hemoglobin binds to 2,3-BPG?

K₀.₅ increases and affinity decreases.

What is the Bohr effect associated with regarding hemoglobin?

Under the Bohr effect, K₀.₅ increases due to decreased affinity.

Why does fetal hemoglobin (HbF) bind 2,3-BPG less tightly than adult hemoglobin?

Because fetal hemoglobin has more positive charges in the BPG-binding pocket.

What curve does myoglobin obey?

Myoglobin shows a hyperbolic binding curve.

Which structure do salt bridges stabilize in the T state of deoxyhemoglobin?

Salt bridges stabilize the tertiary structure.

What are the characteristics of myoglobin compared to hemoglobin?

Myoglobin is monomeric with one heme group; hemoglobin is tetrameric with four heme groups.

How does oxygen binding affect the conformation of ferrous iron in hemoglobin?

The conformation tilts about 60° with respect to the perpendicular of the plane.

What happens to the oxygen-binding curve during alkalosis?

The affinity for O2 increases and the curve shifts left.

How does CO2 affect oxygen release from hemoglobin?

CO2 promotes oxygen release by stabilizing the T-state.

What is the physiological role of 2,3-BPG in oxygen transport?

It acts as a negative allosteric effector, decreasing O2 affinity.

What effect does fetal hemoglobin (HbF) have on O2 binding?

Fetal hemoglobin has a higher affinity for O2 compared to adult hemoglobin.