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ALDH1A1
Aldehyde dehydrogenase 1 family, member A1, also known as ALDH1A1 or retinaldehyde dehydrogenase 1 (RALDH1), is an enzyme that is encoded by the ''ALDH1A1'' gene. Function This protein belongs to the aldehyde dehydrogenases family of proteins and is a member of the ALDH1 subfamily (including ALDH1A2, ALDH1A3, ALDH1B1, ALDH2). Aldehyde dehydrogenase isozymes are NAD(P)-dependent dehydrogenases that catalyze the oxidation of an aldehyde into the corresponding carboxylic acid while reducing NAD+ or NADP+. ALDH1A1 is the only ALDH1 isozyme known to oxidize 9-cis retinaldehyde into 9-cis retinoic acid and thus serve as the only known activator of the Retinoid X receptor alpha, rexinoid nuclear receptor pathway. ALDH1A1 has also been described with activity against other substrates in living systems, including All-Trans-Retinaldehyde, all-trans retinaldehyde as well as oxazaphosphorine, a cyclophosphamide metabolite. Unique among the ALDH1 isozymes, ALDH1A1 is known to possess estera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldehyde Dehydrogenase
Aldehyde dehydrogenases () are a group of enzymes that catalyse the oxidation of aldehydes. They convert aldehydes (R–C(=O)) to carboxylic acids (R–C(=O)). The oxygen comes from a water molecule. To date, nineteen ALDH genes have been identified within the human genome. These genes participate in a wide variety of biological processes including the detoxification of exogenously and endogenously generated aldehydes. Function Aldehyde dehydrogenase is a polymorphic enzyme responsible for the oxidation of aldehydes to carboxylic acids. There are three different classes of these enzymes in mammals: class 1 (low ''K''m, cytosolic), class 2 (low ''K''m, mitochondrial), and class 3 (high ''K''m, such as those expressed in tumors, stomach, and cornea). In all three classes, constitutive and inducible forms exist. ALDH1 and ALDH2 are the most important enzymes for aldehyde oxidation, and both are tetrameric enzymes composed of 54 kDa subunits. These enzymes are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ALDH1A2
Aldehyde dehydrogenase 1 family, member A2, also known as ALDH1A2 or retinaldehyde dehydrogenase 2 (RALDH2), is an enzyme that in humans is encoded by the ''ALDH1A2'' gene. Function ALDH1a2 belongs to the aldehyde dehydrogenase family of proteins, and specifically the ALDH1 family. The product of this gene, ALDH1a2, is an enzyme that catalyzes the synthesis of all-trans retinoic acid (RA) from retinaldehyde in a NAD-dependent manner. Retinoic acid, the active derivative of vitamin A (retinol), is a retinoid nuclear receptor ligand that functions in developing and adult tissues. ALDH1a2 is critical to fetal development by activating the RAR nuclear receptors. Studies of ALDH1a2 in mice suggest that this enzyme and the cytochrome CYP26A1 enzyme coordinate local embryonic retinoic acid levels that facilitate posterior organ development and prevent spina bifida. In adult tissues, ALDH1a2 is known to regulate immune tolerance in the colon and other mucosal tissues by generati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aldehyde Dehydrogenase
Aldehyde dehydrogenases () are a group of enzymes that catalyse the oxidation of aldehydes. They convert aldehydes (R–C(=O)) to carboxylic acids (R–C(=O)). The oxygen comes from a water molecule. To date, nineteen ALDH genes have been identified within the human genome. These genes participate in a wide variety of biological processes including the detoxification of exogenously and endogenously generated aldehydes. Function Aldehyde dehydrogenase is a polymorphic enzyme responsible for the oxidation of aldehydes to carboxylic acids. There are three different classes of these enzymes in mammals: class 1 (low ''K''m, cytosolic), class 2 (low ''K''m, mitochondrial), and class 3 (high ''K''m, such as those expressed in tumors, stomach, and cornea). In all three classes, constitutive and inducible forms exist. ALDH1 and ALDH2 are the most important enzymes for aldehyde oxidation, and both are tetrameric enzymes composed of 54 kDa subunits. These enzymes are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ALDH1A3
Aldehyde dehydrogenase 1 family, member A3 (ALDH1a3), also known as retinaldehyde dehydrogenase 3 (RALDH3) or as ALDH6 in earlier published studies, is an enzyme that in humans is encoded by the ''ALDH1A3'' gene., Function Aldehyde dehydrogenase isozymes are NAD(P)-dependent dehydrogenases that catalyze the oxidation of an aldehyde into the corresponding carboxylic acid while reducing NAD+ or NADP+. ALDH1a3 oxidizes all-trans retinaldehyde into all-trans retinoic acid and thus serves as the final catalytic step in the activation of the retinoid nuclear receptor (RAR) pathway. While ALDH1a3 and related isozymes are known to utilize many aldehyde substrates in biochemical experiments, genetic and functional analysis demonstrates that ALDH1a3 functions only to oxidize all-trans retinaldehyde in living systems. ALDH1a3 exists as a homotetramer with cytosolic localization. It is not known to have any function in healthy adult tissues. ALDH1a3 contains a catalytic cysteine residu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecules known as product (chemistry), products. Almost all metabolism, metabolic processes in the cell (biology), cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme, pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts include Ribozyme, catalytic RNA molecules, also called ribozymes. They are sometimes descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alcohol Metabolism
The pharmacology of ethanol involves both pharmacodynamics (how it affects the body) and pharmacokinetics (how the body processes it). In the body, ethanol primarily affects the central nervous system, acting as a depressant and causing sedation, relaxation, and decreased anxiety. The complete list of mechanisms remains an area of research, but ethanol has been shown to affect ligand-gated ion channels, particularly the GABAA receptor, GABAA receptor. After oral ingestion, ethanol is absorbed via the stomach and intestines into the bloodstream. Ethanol is highly water-soluble and diffuses passively throughout the entire body, including the brain. Soon after ingestion, it begins to be metabolized, 90% or more by the liver. One standard drink is sufficient to almost completely saturate the liver's capacity to metabolize alcohol. The main metabolite is acetaldehyde, a toxic carcinogen. Acetaldehyde is then further metabolized into ionic acetate by the enzyme aldehyde dehydrogenase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crystallin
In anatomy, a crystallin is a water-soluble structural protein found in the lens and the cornea of the eye accounting for the transparency of the structure. It has also been identified in other places such as the heart, and in aggressive breast cancer tumors. The physical origins of eye lens transparency and its relationship to cataract are an active area of research. Since it has been shown that lens injury may promote nerve regeneration, crystallin has been an area of neural research. So far, it has been demonstrated that crystallin β b2 (crybb2) may be a neurite-promoting factor. Function The main function of crystallins at least in the lens of the eye is probably to increase the refractive index while not obstructing light. However, this is not their only function. It has become clear that crystallins may have several metabolic and regulatory functions, both within the lens and in other parts of the body. More proteins containing βγ-crystallin domains have now been char ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cornea
The cornea is the transparency (optics), transparent front part of the eyeball which covers the Iris (anatomy), iris, pupil, and Anterior chamber of eyeball, anterior chamber. Along with the anterior chamber and Lens (anatomy), lens, the cornea Refraction, refracts light, accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is approximately 43 dioptres. The cornea can be reshaped by surgical procedures such as LASIK. While the cornea contributes most of the eye's focusing power, its Focus (optics), focus is fixed. Accommodation (eye), Accommodation (the refocusing of light to better view near objects) is accomplished by changing the geometry of the lens. Medical terms related to the cornea often start with the prefix "''wikt:kerat-, kerat-''" from the Ancient Greek, Greek word κέρας, ''horn''. Structure The cornea has myelinated, unmyelinated nerve endings sensitive to touch, temperature and chemicals; a to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alcoholism
Alcoholism is the continued drinking of alcohol despite it causing problems. Some definitions require evidence of dependence and withdrawal. Problematic use of alcohol has been mentioned in the earliest historical records. The World Health Organization (WHO) estimated there were 283 million people with alcohol use disorders worldwide . The term ''alcoholism'' was first coined in 1852, but ''alcoholism'' and ''alcoholic'' are considered stigmatizing and likely to discourage seeking treatment, so diagnostic terms such as ''alcohol use disorder'' and ''alcohol dependence'' are often used instead in a clinical context. Alcohol is addictive, and heavy long-term alcohol use results in many negative health and social consequences. It can damage all the organ systems, but especially affects the brain, heart, liver, pancreas, and immune system. Heavy alcohol usage can result in trouble sleeping, and severe cognitive issues like dementia, brain damage, or Wernicke–Kors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-nucleotide Polymorphism
In genetics and bioinformatics, a single-nucleotide polymorphism (SNP ; plural SNPs ) is a germline substitution of a single nucleotide at a specific position in the genome. Although certain definitions require the substitution to be present in a sufficiently large fraction of the population (e.g. 1% or more), many publications do not apply such a frequency threshold. For example, a Guanine, G nucleotide present at a specific location in a reference genome may be replaced by an Adenine, A in a minority of individuals. The two possible nucleotide variations of this SNP – G or A – are called alleles. SNPs can help explain differences in susceptibility to a wide range of diseases across a population. For example, a common SNP in the Factor H, CFH gene is associated with increased risk of age-related macular degeneration. Differences in the severity of an illness or response to treatments may also be manifestations of genetic variations caused by SNPs. For example, two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetaldehyde
Acetaldehyde (IUPAC systematic name ethanal) is an organic compound, organic chemical compound with the chemical formula, formula , sometimes abbreviated as . It is a colorless liquid or gas, boiling near room temperature. It is one of the most important aldehydes, occurring widely in nature and being produced on a large scale in industry. Acetaldehyde occurs naturally in coffee, bread, and ripe fruit, and is produced by plants. It is also produced by the partial oxidation of ethanol by the liver enzyme alcohol dehydrogenase and is a contributing cause of hangover after alcohol (drug), alcohol consumption. Pathways of exposure include air, water, land, or groundwater, as well as drink and smoke. Consumption of disulfiram inhibits acetaldehyde dehydrogenase, the enzyme responsible for the metabolism of acetaldehyde, thereby causing it to build up in the body. International Agency for Research on Cancer, The International Agency for Research on Cancer (IARC) has listed acetaldehyde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disulfiram
Disulfiram is a medication used to support the treatment of chronic alcoholism by producing an acute sensitivity to ethanol (drinking alcohol). Disulfiram works by Enzyme inhibition, inhibiting the enzyme aldehyde dehydrogenase (specifically ALDH2), causing many of the effects of a hangover to be felt immediately following alcohol (drug), alcohol consumption. Disulfiram plus alcohol, even small amounts, produces flushing, throbbing in the head and neck, a throbbing headache, respiratory difficulty, nausea, copious vomiting, sweating, thirst, chest pain, palpitation, dyspnea, shortness of breath, hyperventilation, tachycardia, fast heart rate, hypotension, low blood pressure, Syncope (medicine), fainting, marked uneasiness, weakness, vertigo, blurred vision, and confusion. In severe reactions there may be respiratory depression, cardiovascular collapse, arrhythmia, abnormal heart rhythms, myocardial infarction, heart attack, acute congestive heart failure, unconsciousness, convulsi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
