Oxyhemoglobin and carboxyhemoglobin are two different forms of hemoglobins. Hemoglobin is the protein in red blood cells responsible for the delivery of oxygen to the tissues. It contains iron, and almost all vertebrates have hemoglobin except for the fish family known as Channichthyidae.
The key difference between oxyhemoglobin and carboxyhemoglobin is their composition. Oxyhemoglobin is a compound of ferrohemoglobin and oxygen, while carboxyhemoglobin is a compound of ferrohemoglobin and carbon monoxide.
CONTENTS
1. Overview and Key Difference
2. What is Oxyhemoglobin
3. What is Carboxyhemoglobin
4. Similarities – Oxyhemoglobin and Carboxyhemoglobin
5. Oxyhemoglobin vs Carboxyhemoglobin in Tabular Form
6. Summary – Oxyhemoglobin vs Carboxyhemoglobin
7. FAQ – Oxyhemoglobin and Carboxyhemoglobin
What is Oxyhemoglobin?
Oxyhemoglobin is the normal, oxygen-carrying form of hemoglobin. In this compound, the iron is in the reduced (ferrous) state. Hemoglobin usually forms an unstable, reversible bond with oxygen. In the oxygenated state, it is called oxyhemoglobin, and this compound is bright red. However, in the reduced state, it is purplish blue in color.
Figure 01: Oxyhemoglobin
Hemoglobin is the respiratory pigment present in RBCs. Oxyhemoglobin is formed in the lungs. Furthermore, the main function of oxyhemoglobin is its role in the transport of oxygen from the lungs to various tissues.
What is Carboxyhemoglobin?
Carboxyhemoglobin is a stable compound of carbon monoxide and hemoglobin. It forms in red blood cells upon contact with carbon monoxide gas. Carbon monoxide (CO) is a colorless, odorless, and tasteless gas. The affinity of CO to hemoglobin is usually high, which is about 200-250 times greater than its affinity for oxygen.
Figure 02: Forms of Hemoglobin
Moreover, the formation of carboxyhemoglobin drastically reduces the amount of oxygen transported through the bloodstream. The process can quickly lead to tissue hypoxia. It is a dangerous condition where body tissues are deprived of adequate oxygen molecules. Severe health consequences resulting in this condition include organ damage and potentially death.
Similarities Between Oxyhemoglobin and Carboxyhemoglobin
- Oxyhemoglobin and carboxyhemoglobin are two different forms of hemoglobins.
- They are compounds made by combining proteins and gases.
- Both are formed in the RBCs.
- Both compounds are normally red in color.
Difference Between Oxyhemoglobin and Carboxyhemoglobin
Definition
- Hemoglobin (O2Hb) that is bound with oxygen is known as oxyhaemoglobin.
- Hemoglobin (COHb or HbCO) that is bound with carbon monoxide is known as carboxyhemoglobin.
Color of the Compound
- Oxyhaemoglobin is bright red in color.
- Carboxyhemoglobin is cherry red in color.
Function
- Oxyhaemoglobin is required for the transport of oxygen from the lungs to various tissues.
- Carboxyhemoglobin has no function; instead, it causes a disease.
Associated Diseases
- Oxyhaemoglobin is found in normal RBCs and is not associated with diseases.
- Carboxyhemoglobin causes a disease called carbon monoxide poisoning.
Treatment
- There is no need for treatment.
- The treatments for carboxyhemoglobin include breathing pure oxygen and getting treatment in an oxygen chamber.
The following table summarizes the difference between oxyhemoglobin and carboxyhemoglobin.
Summary – Oxyhemoglobin vs Carboxyhemoglobin
Oxyhemoglobin and carboxyhemoglobin are two different forms of hemoglobins. Hemoglobin that has been bonded to oxygen is called oxyhemoglobin, while carboxyhemoglobin is formed when hemoglobin is exposed to carbon monoxide. Furthermore, oxyhemoglobin is the form of hemoglobin that delivers oxygen to tissues from the lungs. However, carboxyhemoglobin does not have any function; instead, it causes a disease called carbon monoxide poisoning. This is the summary of the difference between oxyhemoglobin and carboxyhemoglobin.
FAQ: Oxyhemoglobin and Carboxyhemoglobin
1. What causes oxyhemoglobin?
- There are several situations that can increase hemoglobin’s affinity for oxygen. Oxygen strongly binds to hemoglobin when it decreases hydrogen ions, PaCO2, temperature, and 2-3-DPG.
2. What is a normal hemoglobin level?
- Normal levels of hemoglobin for adults vary, but in general, they are, for males, 13.8 to 17.2 grams per deciliter (g/dL) and for females, 12.1 to 15.1 g/dL.
3. What happens if hemoglobin is low?
- When there are not sufficient healthy red blood cells or hemoglobin to carry oxygen to the tissues of the body, it causes a condition called anemia. Anemia can cause weakness, tiredness, and shortness of breath.
4. What is the function of the carboxyhemoglobin?
- Carboxyhemoglobin (COHb) is a stable complex of hemoglobin and carbon monoxide that forms in red blood cells when carbon monoxide is inhaled. It is also useful in monitoring the treatment of carbon monoxide poisoning.
5. What is the priority treatment for carbon monoxide poisoning?
- Carbon monoxide poisoning is treated with delivering 100% oxygen into the blood cells. Depending on the severity of the exposure, oxygen is delivered in different ways. For mild poisoning, oxygen is delivered through a mask, while for severe carbon monoxide poisoning, the full body is placed in a high-pressure chamber.
Reference:
1. “Oxyhemoglobin – An Overview.” ScienceDirect Topics.
2. Tany Thaniyavarn. “Carboxyhemoglobin.” Reference Range, Interpretation, Collection and Panels, Medscape.
Image Courtesy:
1. “OxyHemoglobin Active Site” By PDB code 2DN11.25 a resolution crystal structures of human haemoglobin in the oxy, deoxy and carbonmonoxy forms.Park, S.-Y., Yokoyama, T., Shibayama, N., Shiro, Y., Tame, J.R.(2006) J Mol Biol 360: 690-701DOI: 10.1016/j.jmb.2006.05.036 (CC0) via Commons Wikimedia
2. “Structures of Hemoglobin forms” By Gladissk – marvin sketch (CC BY-SA 3.0) via Commons Wikimedia
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