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Carboxyhemoglobin
Carboxyhemoglobin (carboxyhaemoglobin BrE) (symbol COHb or HbCO) is a stable complex (chemistry), complex of carbon monoxide and hemoglobin (Hb) that forms in red blood cells upon contact with carbon monoxide. Carboxyhemoglobin is often mistaken for the compound formed by the combination of carbon dioxide (Carboxylic acid, carboxyl) and hemoglobin, which is actually carbaminohemoglobin. Carboxyhemoglobin terminology emerged when carbon monoxide was known by its historic name, "carbonic oxide", and evolved through Germanic and British English etymological influences; the preferred IUPAC nomenclature is carbonylhemoglobin. The average non-smoker maintains a systemic carboxyhemoglobin level under 3% COHb whereas smokers approach 10% COHb. The biological threshold for carboxyhemoglobin tolerance is 15% COHb, meaning toxicity is consistently observed at levels in excess of this concentration. The FDA has previously set a threshold of 14% COHb in certain clinical trials evaluating the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Monoxide Poisoning
Carbon monoxide poisoning typically occurs from breathing in carbon monoxide (CO) at excessive levels. Symptoms are often described as " flu-like" and commonly include headache, dizziness, weakness, vomiting, chest pain, and confusion. Large exposures can result in loss of consciousness, arrhythmias, seizures, or death. The classically described "cherry red skin" rarely occurs. Long-term complications may include chronic fatigue, trouble with memory, and movement problems. CO is a colorless and odorless gas which is initially non-irritating. It is produced during incomplete burning of organic matter. This can occur from motor vehicles, heaters, or cooking equipment that run on carbon-based fuels. Carbon monoxide primarily causes adverse effects by combining with hemoglobin to form carboxyhemoglobin (symbol COHb or HbCO) preventing the blood from carrying oxygen and expelling carbon dioxide as carbaminohemoglobin. Additionally, many other hemoproteins such as myoglob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heme Oxygenase
Heme oxygenase, or haem oxygenase, (HMOX, commonly abbreviated as HO) is an enzyme that catalyzes the degradation of heme to produce biliverdin, ferrous iron, and carbon monoxide. There are many heme degrading enzymes in nature. In general, only aerobic heme degrading enzymes are referred to as HMOX-like enzymes whereas anaerobic enzymes are typically not affiliated with the HMOX family. Heme oxygenase Heme oxygenase (alternatively spelled using haem or oxidase) catalyzes the degradation of heme to biliverdin/bilirubin, ferrous ion, and carbon monoxide. The human genome may encode three isoforms of HMOX. The degradation of heme forms three distinct chromogens as seen in healing cycle of a bruise. This reaction can occur in virtually every cell and platelet; the classic example is the healing process of a contusion, which forms different chromogens as it gradually heals: (red) heme to (green) biliverdin to (yellow) bilirubin which is widely known for jaundice. In general, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemoglobin
Hemoglobin (haemoglobin, Hb or Hgb) 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 (lungs or gills) 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 12to 20grams of hemoglobin in every 100mL of blood. Hemoglobin is a metalloprotein, a chromoprotein, and a globulin. In mammals, hemoglobin makes up about 96% of a red blood cell's dry matter, dry weight (excluding water), and around 35% of the total weight (including water). Hemoglobin has an oxygen-binding capacity of 1.34mL of O2 per gram, which increases the total blood oxygen capacity seventy-fold compared to dissolved oxygen in blood plasma alone. The mammalian hemoglobin molecule can bind and transport up to four ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Blood Cell
Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood cell and the vertebrate's principal means of delivering oxygen () to the body tissue (biology), tissues—via blood flow through the circulatory system. Erythrocytes take up oxygen in the lungs, or in fish the gills, and release it into tissues while squeezing through the body's capillary, capillaries. The cytoplasm of a red blood cell is rich in hemoglobin (Hb), an iron-containing biomolecule that can bind oxygen and is responsible for the red color of the cells and the blood. Each human red blood cell contains approximately 270 million hemoglobin molecules. The cell membrane is composed of proteins and lipids, and this structure provides properties essential for physiological Cell (biology), cell function such as erythrocyte deformabil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gasotransmitter
Gasotransmitters is a class of neurotransmitters. The molecules are distinguished from other bioactive endogenous gaseous signaling molecules based on a need to meet distinct characterization criteria. Currently, only nitric oxide, carbon monoxide, and hydrogen sulfide are accepted as gasotransmitters. According to in vitro models, gasotransmitters, like other gaseous signaling molecules, may bind to gasoreceptors and trigger signaling in the cells. The name gasotransmitter is not intended to suggest a gaseous physical state such as infinitesimally small gas bubbles; the physical state is dissolution in complex body fluids and cytosol. These particular gases share many common features in their production and function but carry on their tasks in unique ways which differ from classical signaling molecules. Criteria The terminology and characterization criteria of “gasotransmitter” were first introduced in 2002. For one gas molecule to be categorized as a gasotransmitter, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erythrocyte
Red blood cells (RBCs), referred to as erythrocytes (, with -''cyte'' translated as 'cell' in modern usage) in academia and medical publishing, also known as red cells, erythroid cells, and rarely haematids, are the most common type of blood cell and the vertebrate's principal means of delivering oxygen () to the body tissues—via blood flow through the circulatory system. Erythrocytes take up oxygen in the lungs, or in fish the gills, and release it into tissues while squeezing through the body's capillaries. The cytoplasm of a red blood cell is rich in hemoglobin (Hb), an iron-containing biomolecule that can bind oxygen and is responsible for the red color of the cells and the blood. Each human red blood cell contains approximately 270 million hemoglobin molecules. The cell membrane is composed of proteins and lipids, and this structure provides properties essential for physiological cell function such as deformability and stability of the blood cell while traversing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbaminohemoglobin
Carbaminohemoglobin (carbaminohaemoglobin BrE) (CO2Hb, also known as carbhemoglobin and carbohemoglobin) is a Chemical compound, compound of hemoglobin and carbon dioxide, and is one of the forms in which carbon dioxide exists in the blood. In blood, 23% of carbon dioxide is carried this way, while 70% is converted into bicarbonate by carbonic anhydrase and then carried in plasma, and 7% carried as free CO2, dissolved in plasma. Structure The structure of carbaminohemoglobin can be described as the binding of carbon dioxide to the amino groups of the globin chains of hemoglobin. This occurs at the N-terminals of the globin chains and at the amino sidebranches of arginine and lysine residues. The process of carbon dioxide binding to hemoglobin is generally known as carbamino formation. This is the source from where the protein gets its name, as it is a combination of carbamino and hemoglobin. Function One of the primary functions of carbaminohemoglobin is to enable the trans ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemoprotein
A hemeprotein (or haemprotein; also hemoprotein or haemoprotein), 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. The heme consists of iron cation bound at the center of the conjugate base of the porphyrin, as well as other ligands attached to the "axial sites" of the iron. The porphyrin ring is a planar dianionic, tetradentate ligand. The iron is typically Fe2+ or Fe3+. One or two ligands are attached at the axial sites. The porphyrin ring has four nitrogen atoms that bind to the iron, leaving two other coordination positions of the iron available for bonding to the histidine of the protein and a divalent atom. Hemeproteins probably evolved to incorporate the iron atom contained within the protoporphyrin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foetal
A fetus or foetus (; : fetuses, foetuses, rarely feti or foeti) is the unborn offspring of a viviparous animal that develops from an embryo. Following the embryonic development, embryonic stage, the fetal stage of development takes place. Prenatal development is a continuum, with no clear defining feature distinguishing an embryo from a fetus. However, in general a fetus is characterized by the presence of all the major body organs, though they will not yet be fully developed and functional, and some may not yet be situated in their final Anatomy, anatomical location. In human prenatal development, fetal development begins from the ninth week after Human fertilization, fertilization (which is the eleventh week of Gestational age (obstetrics), gestational age) and continues until the childbirth, birth of a newborn. Etymology The word ''wikt:fetus#English, fetus'' (plural ''wikt:fetuses#English, fetuses'' or rarely, the solecism ''wikt:feti#English, feti''''Oxford English Dict ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hemoglobin Variants
Hemoglobin is a protein that transports oxygen in the blood. Genetic differences lead to structural variants in the hemoglobin protein structure. Some variants can cause disease while others have little to no effect. The normal hemoglobin types are Hemoglobin A (HbA), which makes up 95–98% of total hemoglobin in adults, Hemoglobin A2 (HbA2), which constitutes 2–3% of total hemoglobin in adults, and Hemoglobin F (HbF), which is the predominant hemoglobin in the fetus during pregnancy, and may persist in small amounts in adults. Hemoglobin variants occur when there are mutations in specific genes that code for the protein chains, known as globins, which make up the hemoglobin molecule. This leads to amino acid Amino acid replacement, substitutions in the hemoglobin molecule that could affect the structure, properties, and/or the stability of the hemoglobin molecule. There are over 1,000 naturally occurring structural variants of hemoglobin in humans. Effects of variants The ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CYP3A
Cytochrome P450, family 3, subfamily A, also known as CYP3A, is a human gene locus. A homologous locus is found in mice. These genes encode monooxygenases which catalyze many reactions involved in the synthesis of cholesterol, steroids and other lipids as well as drug metabolism. The CYP3A locus includes all the known members of the 3A subfamily of the cytochrome P450 superfamily of genes. The CYP3A cluster consists of four genes: * CYP3A4, * CYP3A5, * CYP3A7, and * CYP3A43. The region also contains four pseudogenes: * , * , * , and * . as well as several extra exons which may or may not be included in transcripts produced from this region. Previously another CYP3A member, CYP3A3, was thought to exist; however, it is now thought that this sequence represents a transcript variant of CYP3A4. Structure Structurally, the key to the CYP3A enzyme’s large range of activity is the heme cofactor and the P450 protein fold, an oxidation reaction through molecular oxygen and NADPH. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytochrome P450
Cytochromes P450 (P450s or CYPs) are a Protein superfamily, superfamily of enzymes containing heme as a cofactor (biochemistry), cofactor that mostly, but not exclusively, function as monooxygenases. However, they are not omnipresent; for example, they have not been found in ''Escherichia coli''. In mammals, these enzymes oxidize steroids, fatty acids, xenobiotics, and participate in many biosyntheses. By hydroxylation, CYP450 enzymes convert xenobiotics into hydrophilic derivatives, which are more readily excreted. P450s are, in general, the terminal oxidase enzymes in electron transfer chains, broadly categorized as P450-containing systems. The term "P450" is derived from the spectrophotometry, spectrophotometric peak at the wavelength of the absorption spectroscopy, absorption maximum of the enzyme (450 nanometre, nm) when it is in the redox, reduced state and complexed with carbon monoxide. Most P450s require a protein partner to deliver one or more electrons to reduc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
