Hemoglobin is a protein containing iron that facilitates the transportation of oxygen in red blood cells. Almost all vertebrates contain hemoglobin, with the sole exception of the fish family Channichthyidae. Hemoglobin in the blood carries oxygen from the respiratory organs to the other tissues of the body, where it releases the oxygen to enable aerobic respiration which powers an animal's metabolism. A healthy human has 12 to 20 grams of hemoglobin in every 100 mL of blood. Hemoglobin is a metalloprotein, a chromoprotein, and globulin.
Hemoglobinopathy is the medical term for a group of inherited blood disorders involving the hemoglobin, the protein of red blood cells. They are single-gene disorders and, in most cases, they are inherited as autosomal co-dominant traits.
Myoglobin is an iron- and oxygen-binding protein found in the cardiac and skeletal muscle tissue of vertebrates in general and in almost all mammals. Myoglobin is distantly related to hemoglobin. Compared to hemoglobin, myoglobin has a higher affinity for oxygen and does not have cooperative binding with oxygen like hemoglobin does. Myoglobin consists of non-polar amino acids at the core of the globulin, where the heme group is non-covalently bounded with the surrounding polypeptide of myoglobin. In humans, myoglobin is found in the bloodstream only after muscle injury.
A hemeprotein, or heme protein, is a protein that contains a heme prosthetic group. They are a very large class of metalloproteins. The heme group confers functionality, which can include oxygen carrying, oxygen reduction, electron transfer, and other processes. Heme is bound to the protein either covalently or noncovalently or both.
Leghemoglobin is an oxygen-carrying phytoglobin found in the nitrogen-fixing root nodules of leguminous plants. It is produced by these plants in response to the roots being colonized by nitrogen-fixing bacteria, termed rhizobia, as part of the symbiotic interaction between plant and bacterium: roots not colonized by Rhizobium do not synthesise leghemoglobin. Leghemoglobin has close chemical and structural similarities to hemoglobin, and, like hemoglobin, is red in colour. It was originally thought that the heme prosthetic group for plant leghemoglobin was provided by the bacterial symbiont within symbiotic root nodules. However, subsequent work shows that the plant host strongly expresses heme biosynthesis genes within nodules, and that activation of those genes correlates with leghemoglobin gene expression in developing nodules.
Heme, or haem, is a ring-shaped iron-containing molecular component of hemoglobin, which is necessary to bind oxygen in the bloodstream. It is composed of four pyrrole rings with 2 vinyl and 2 propionic acid side chains. Heme is biosynthesized in both the bone marrow and the liver.
The globins are a superfamily of heme-containing globular proteins, involved in binding and/or transporting oxygen. These proteins all incorporate the globin fold, a series of eight alpha helical segments. Two prominent members include myoglobin and hemoglobin. Both of these proteins reversibly bind oxygen via a heme prosthetic group. They are widely distributed in many organisms.
Hemolymph, or haemolymph, is a fluid, analogous to the blood in vertebrates, that circulates in the interior of the arthropod (invertebrate) body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which hemolymph cells called hemocytes are suspended. In addition to hemocytes, the plasma also contains many chemicals. It is the major tissue type of the open circulatory system characteristic of arthropods. In addition, some non-arthropods such as mollusks possess a hemolymphatic circulatory system.
Hemopexin, also known as beta-1B-glycoprotein, is a glycoprotein that in humans is encoded by the HPX gene and belongs to the hemopexin family of proteins. Hemopexin is the plasma protein with the highest binding affinity for heme.
Neuroglobin is a member of the vertebrate globin family involved in cellular oxygen homeostasis and reactive oxygen/nitrogen scavenging. It is an intracellular hemoprotein expressed in the central and peripheral nervous system, cerebrospinal fluid, retina and endocrine tissues. Neuroglobin is a monomer that reversibly binds oxygen with an affinity higher than that of hemoglobin. It also increases oxygen availability to brain tissue and provides protection under hypoxic or ischemic conditions, potentially limiting brain damage. Neuroglobin were in the past found only in vertebrate neurons, but recently in 2013, were found in the neurons of unrelated protostomes, like photosynthetic acoel as well as radiata such as jellyfish. In addition to neurons, neuroglobin is present in astrocytes in certain pathologies of the rodent brain and in the physiological seal brain. This is thought to be due to convergent evolution. It is of ancient evolutionary origin, and is homologous to nerve globins of invertebrates. Recent research confirmed the presence of human neuroglobin protein in cerebrospinal fluid (CSF).
Erythrocruorin, and the similar chlorocruorin, are large oxygen-carrying hemeprotein complexes, which have a molecular mass greater than 3.5 million daltons. Both are sometimes called giant hemoglobin or hexagonal bilayer haemoglobin. They are found in many annelids and arthropods.
Hepatic stellate cells (HSC), also known as perisinusoidal cells or Ito cells, are pericytes found in the perisinusoidal space of the liver, also known as the space of Disse. The stellate cell is the major cell type involved in liver fibrosis, which is the formation of scar tissue in response to liver damage, in addition these cells store and concentrate vitamin A.
Nitric oxide dioxygenase (EC 1.14.12.17) is an enzyme that catalyzes the conversion of nitric oxide (NO) to nitrate (NO−
3) . The net reaction for the reaction catalyzed by nitric oxide dioxygenase is shown below:
Protein-arginine deiminase type-4, is a human protein which in humans is encoded by the PADI4 gene. The protein as an enzyme, specifically protein-arginine deiminase, a type of hydrolase.
Transcription regulator protein BACH1 is a protein that in humans is encoded by the BACH1 gene.
Nuclear factor erythroid 2-related factor 1 (Nrf1) also known as nuclear factor erythroid-2-like 1 (NFE2L1) is a protein that in humans is encoded by the NFE2L1 gene. Since NFE2L1 is referred to as Nrf1, it is often confused with nuclear respiratory factor 1 (Nrf1).
Dihydropyrimidinase-related protein 3 is an enzyme that in humans is encoded by the DPYSL3 gene. A recent bioinformatics study suggested that the DPYSL3 gene might have a prognostic role in neuroblastoma.
Transcription factor MafF is a bZip Maf transcription factor protein that in humans is encoded by the MAFF gene.
Cysteine and glycine-rich protein 2 is a protein that in humans is encoded by the CSRP2 gene.
Delta-aminolevulinate synthase 1 also known as ALAS1 is a protein that in humans is encoded by the ALAS1 gene. ALAS1 is an aminolevulinic acid synthase.
