Introduction
Hemoglobin is an iron-rich protein present in red blood cells. The protein enables the transport of oxygen throughout the body. Each hemoglobin contains four atoms of iron, enabling the transport of four oxygen molecules. Hemoglobin is also responsible for the transport of carbon dioxide back to the lungs. Hemoglobin derivatives are formed by alteration in the protein molecule. The hemoglobin derivatives can be of normal or abnormal type. The derivatives are visualized under spectroscopy. These altered heme proteins can cause various medical complications.
What Are Hemoglobin Derivatives?
Hemoglobin is a red color protein in blood cells that transports oxygen and carbon dioxide between lungs and body tissue. Hemoglobin derivatives are altered forms of hemoglobin. The derivatives are formed by the combination of different ligands in the heme part or changes in the oxidation state of iron.
What Are the Different Derivatives of Hemoglobin?
Normal derivatives include oxyhemoglobin, deoxyhemoglobin, and carbaminohemoglobin. Abnormal derivatives include methemoglobin, carboxyhemoglobin, and sulfhemoglobin.
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Methemoglobin: The iron present in hemoglobin is altered, making it inefficient to transport oxygen. The ferrous state of iron is oxidized to a ferric state in methemoglobin. Methemoglobin appears dark brown in color. Specific drugs or nitrate compounds in the bloodstream may cause this condition to develop. The normal range of methemoglobin is less than two percent of total hemoglobin. The reverse reduction of methemoglobin to hemoglobin is controlled by NADH-dependent cytochrome B5 reductase. Trace amounts of methemoglobin are reduced to normal states by methemoglobin reductase enzymes. The important feature of methemoglobin is it can be used to overcome cyanide poisoning.
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Carboxyhemoglobin: It is an abnormal type of hemoglobin that combines with carbon monoxide instead of oxygen or carbon dioxide. Carbon monoxide has a high affinity to hemoglobin than oxygen. A high amount of this abnormal hemoglobin can hinder the normal transport of oxygen. The normal range of carboxyhemoglobin is 1.5 percent of total hemoglobin. However, smokers may have up to nine percent of total hemoglobin.
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Sulfhemoglobin: It is a rare and abnormal type of hemoglobin that is unable to transport oxygen. The condition is induced by the association of oxygenated hemoglobin with hydrogen sulfide. Medications like Dapsone, Metoclopramide, Nitrates, or Sulfonamides may induce this effect. The condition can not be reversed to oxyhemoglobin. Normally sulfhemoglobin is untraceable in the human bloodstream.
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Carbaminohemoglobin: When hemoglobin binds to carbon dioxide in the tissue, it forms carbaminohemoglobin. Carbon dioxide binds to the alpha-amino group at the end of each polypeptide chain of hemoglobin. As carbon dioxide binds to hemoglobin, the oxygen gets released.
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Oxyhemoglobin and Deoxyhemoglobin: Oxygen-carrying hemoglobin is referred to as oxyhemoglobin. Each hemoglobin can bind with four molecules of oxygen. When the oxygen molecule is released, they form deoxyhemoglobin. Oxyhemoglobin appears bright red, whereas deoxyhemoglobin appears dark red in color.
How Is Hemoglobin Derivative Analyzed With Spectroscopy?
A high level of hemoglobin derivative can cause major health problems by altering hemoglobin and limiting the proper transport of oxygen in the body. It can result in tissue death.
The carboxyhemoglobin test can detect carbon monoxide poisoning in the body. The test is necessary to identify alterations induced in hemoglobin caused by specific drugs. The drugs can result in permanent chemical changes in hemoglobin.
Spectrometric methods are devised for the determination of hemoglobin and its derivatives. It is a non-invasive technique utilizing a light-guided spectrometer for the measurement of hemoglobin and its derivative concentration. Hemoglobin and its derivatives have characteristic spectra in the visible region of light, which are used for rapid identification and analysis. Most hemoproteins have absorption maxima in the sorbet band of 400 to 430 nm (nanometer). When colored solutions of hemoglobin derivatives are visualized through a spectroscope, dark lines or bands are seen in the different light spectrums due to the absorption of light by hemoglobin derivatives.
Oxyhemoglobin shows two bands under spectroscopy. The first band appears in the 541 nm range, and the second band in the 577 nm range. Deoxyhemoglobin has only one band of 542 nm when examined under a spectroscope. Methemoglobin has two bands when reviewed under a microscope. The first band is in the 542 nm range, and the second band is in the 633 nm range. Carboxyhemoglobin has a first band in 535 nm and a second band in the 570 nm range. Sulfhemoglobin has a narrow band in the 650 nm range.
What Is the Clinical Implication of Hemoglobin Derivatives?
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Carbon Monoxide Poisoning: Carbon monoxide is a colorless, odorless gas formed by incomplete combustion. It is an occupational hazard among individuals working in mines. In addition, inhaling automobile gases in enclosed spaces is a common cause of poisoning. At 10 to 20 percent saturation, symptoms of carbon monoxide poisoning begin to appear. Carboxyhemoglobin is evident when levels in the blood exceed 30 percent. The symptoms that appear are breathlessness, headache, nausea, vomiting, and chest pain. If the saturation exceeds 40 to 60 percent, death may occur. Individuals with carbon monoxide poisoning have a cherry red appearance of skin. The condition can be treated with continuous oxygen therapy at high pressure.
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Methemoglobinemia: An elevated level of methemoglobin in blood termed methemoglobinemia is characterized by cyanosis (bluish discoloration of the skin). The condition can be congenital or acquired. In patients with 10 percent saturation, cyanosis develops. When the blood saturation of methemoglobin is between 35 to 40 percent, the affected individuals experience headaches and shortness of breath. Lethargy and stupor develop over 60 percent saturation. The condition can be fatal to patients when 70 percent saturation is attained.
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Congenital Methemoglobinemia: Genetic mutations in the hemoglobin M or congenital defect in NADH-dependent (Nicotinamide adenine dinucleotide) cytochrome B5 reductase can cause congenital methemoglobinemia at birth. If there is a reduction of cytochrome B5 reductase, cyanosis is visible since birth. Almost 10 to 15 percent of total hemoglobin in the bloodstream is methemoglobin. Orally administering methylene blue or ascorbic acid can reduce methemoglobin in the blood and reverse cyanosis.
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Acquired Methemoglobinemia: The condition develops due to the consumption of water containing nitrates or absorption of aniline dyes. Acquired methemoglobinemia may also be caused by Acetaminophen, Phenacetin, Sulphanilamide, Amyl nitrite, and Sodium nitroprusside.
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Sulfhemoglobinemia: If the sulfhemoglobin levels reach 10 grams per deciliter of blood volume, they may cause cyanosis due to lack of oxygen supply. There is no specific treatment required to resolve the condition. Turnover of RBC (red blood cells) can reduce sulfhemoglobin levels in the blood.
Conclusion
Hemoglobin derivatives are an alteration occurring in hemoglobin protein. The altered protein can be of abnormal type. The normal derivatives are frequently found in the bloodstream and do not cause health concerns. The abnormal derivatives, if present in trace amounts, do not cause significant health effects. However, a greater concentration of abnormal derivatives can result in major health problems and tissue death due to hypoxia. It is important to diagnose the condition early and treat them to prevent further complications.
