Medical research

An artificial blood substitute from Transylvania

(Medical Xpress)—Researchers in Cluj-Napoca, Romania, have recently made some significant advances in developing artificial blood substitutes. Their formulation is based not on synthetic hemoglobins, but rather on hemerythrin ...

Medical research

Nitric oxide could make blood transfusions safer

(Medical Xpress)—Blood transfusions are supposed to save lives. Doctors give transfusions to severely ill or injured people with the expectation that their conditions will improve. In fact, transfusions do not always help ...

Neuroscience

Balancing mitochondrial dynamics in Alzheimer's disease

(Medical Xpress)—Many diseases are multifactorial and can not be understood by simple molecular associations alone. Alzheimer's disease (AD)is associated with toxic transformations in two classes of protein,amyloid beta ...

Medical research

New genetic weapons challenge sickle cell disease

Help for patients with sickle cell disease may soon come from gene editing to fix the mutation that causes the disease and boost the patient's own protective fetal hemoglobin.

Medical research

No bleeding required: Anemia detection via smartphone

Biomedical engineers have developed a smartphone app for the non-invasive detection of anemia. Instead of a blood test, the app uses photos of someone's fingernails taken on a smartphone to accurately measure how much hemoglobin ...

Medical research

How stress controls hemoglobin levels in blood

Our ability to breathe oxygen is critical to our survival. This process is mediated by the hemoglobin in our blood, which carries oxygen. Since air contains less oxygen on high mountains, the body is under pressure to make ...

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Hemoglobin

Hemoglobin (English pronunciation: /hiːməˈɡloʊbɪn/; also rendered as haemoglobin and abbreviated Hb or Hgb) is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates. Hemoglobin in the blood carries oxygen from the respiratory organs (lungs or gills) to the rest of the body (i.e., the tissues) where it releases the oxygen to burn nutrients to provide energy to power the functions of the organism, and collects the resultant carbon dioxide to bring it back to the respiratory organs to be dispensed from the organism.

In mammals, the protein makes up about 97% of the red blood cells' dry content, and around 35% of the total content (including water).[citation needed] Hemoglobin has an oxygen binding capacity of 1.34 ml O2 per gram of hemoglobin, which increases the total blood oxygen capacity seventy-fold compared to dissolved oxygen in blood. The mammalian hemoglobin molecule can bind (carry) up to four oxygen molecules.

Hemoglobin is involved in the transport of other gases: it carries some of the body's respiratory carbon dioxide (about 10% of the total) as carbaminohemoglobin, in which CO2 is bound to the globin protein. The molecule also carries the important regulatory molecule nitric oxide bound to a globin protein thiol group, releasing it at the same time as oxygen.

Hemoglobin is also found outside red blood cells and their progenitor lines. Other cells that contain hemoglobin include the A9 dopaminergic neurons in the substantia nigra, macrophages, alveolar cells, and mesangial cells in the kidney. In these tissues, hemoglobin has a non-oxygen-carrying function as an antioxidant and a regulator of iron metabolism.

Hemoglobin and hemoglobin-like molecules are also found in many invertebrates, fungi, and plants. In these organisms, hemoglobins may carry oxygen, or they may act to transport and regulate other things such as carbon dioxide, nitric oxide, hydrogen sulfide and sulfide. A variant of the molecule, called leghemoglobin, is used to scavenge oxygen, to keep it from poisoning anaerobic systems, such as nitrogen-fixing nodules of leguminous plants.

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