|
Klotho (biology)
Klotho is an enzyme that in humans is encoded by the ''KL'' gene. There are three subfamilies of klotho: α-klotho, β-klotho, and γ-klotho. α-klotho activates FGF23, and β-klotho activates FGF19 and FGF21. When the subfamily is not specified, the word "klotho" often means the α-klotho subfamily, because α-klotho was discovered before the other subfamily members. α-klotho is highly expressed in the brain, liver and kidney. β-klotho is predominantly expressed in the liver. γ-klotho is expressed in the skin. Klotho can exist in a membrane-bound form or a (hormonal) soluble, circulating form. Proteases can convert the membrane-bound form into the circulating form. The ''KL'' gene encodes a type-I single-pass transmembrane protein that is related to β-glucuronidases. Reduced production of this protein has been observed in patients with chronic kidney failure (CKF), and this may be one of the factors underlying the degenerative processes (e.g., arteriosclerosis, osteoporosi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the 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 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 are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dalton (unit)
The dalton or unified atomic mass unit (symbols: Da or u) is a non-SI unit of mass widely used in physics and chemistry. It is defined as of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest. The atomic mass constant, denoted ''m''u, is defined identically, giving . This unit is commonly used in physics and chemistry to express the mass of atomic-scale objects, such as atoms, molecules, and elementary particles, both for discrete instances and multiple types of ensemble averages. For example, an atom of helium-4 has a mass of . This is an intrinsic property of the isotope and all helium-4 atoms have the same mass. Acetylsalicylic acid (aspirin), , has an average mass of approximately . However, there are no acetylsalicylic acid molecules with this mass. The two most common masses of individual acetylsalicylic acid molecules are , having the most common isotopes, and , in which one carbon is carbon-13. The molecular mass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucuronide
A glucuronide, also known as glucuronoside, is any substance produced by linking glucuronic acid to another substance via a glycosidic bond. The glucuronides belong to the glycosides. Glucuronidation, the conversion of chemical compounds to glucuronides, is a method that animals use to assist in the excretion of toxic substances, drugs or other substances that cannot be used as an energy source. Glucuronic acid is attached via a glycosidic bond to the substance, and the resulting glucuronide, which has a much higher water solubility than the original substance, is eventually excreted by the kidneys. Enzymes that cleave the glycosidic bond of a glucuronide are called glucuronidases. Examples * Miquelianin (Quercetin 3-O-glucuronide) * Morphine-6-glucuronide * Scutellarein-7-glucuronide Scutellarin is a flavone, a type of phenolic chemical compound. It can be found in the plants '' Scutellaria barbata'' and '' S. lateriflora'' which have been used in traditional medicine''.'' T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steroid
A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and as signaling molecules. Hundreds of steroids are found in plants, animals and fungi. All steroids are manufactured in cells from the sterols lanosterol (opisthokonts) or cycloartenol (plants). Lanosterol and cycloartenol are derived from the cyclization of the triterpene squalene. The steroid core structure is typically composed of seventeen carbon atoms, bonded in four " fused" rings: three six-member cyclohexane rings (rings A, B and C in the first illustration) and one five-member cyclopentane ring (the D ring). Steroids vary by the functional groups attached to this four-ring core and by the oxidation state of the rings. Sterols are forms of steroids with a hydroxy group at position three and a skeleton derived from cholestane. ''A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme Commission Number
The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. As a system of enzyme nomenclature, every EC number is associated with a recommended name for the corresponding enzyme-catalyzed reaction. EC numbers do not specify enzymes but enzyme-catalyzed reactions. If different enzymes (for instance from different organisms) catalyze the same reaction, then they receive the same EC number. Furthermore, through convergent evolution, completely different protein folds can catalyze an identical reaction (these are sometimes called non-homologous isofunctional enzymes) and therefore would be assigned the same EC number. By contrast, UniProt identifiers uniquely specify a protein by its amino acid sequence. Format of number Every enzyme code consists of the letters "EC" followed by four numbers separated by periods. Those numbers represent a progressively finer classification of the enzyme. Preliminary EC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta-glucosidase
β-Glucosidase (EC 3.2.1.21; systematic name β-D-glucoside glucohydrolase) is an enzyme that catalyses the following reaction: : Hydrolysis of terminal, non-reducing β-D-glucosyl residues with release of β-D-glucose Structure β-Glucosidase is composed of two polypeptide chains. Each chain is made up of 438 amino acids and constitute a subunit of the enzyme. Each of these subunits contains an active site. The active site has three potential components: the pocket, the cleft, and the tunnel. The pocket structure is beneficial for recognition of monosaccharide like glucose. The cleft allows for binding of sugars to form polysaccharides. The tunnel allows for the enzyme to attach to polysaccharide and then release product while still attached to the sugar. Function The function of the enzyme is to perform hydrolysis of various glycosides and oligosaccharides. The most significant oligosaccharide β-glucosidase reacts with is cellulose. Cellulose is a polymer composed of β-1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature Reviews Nephrology
''Nature Reviews Nephrology'' is a monthly peer-reviewed review journal published by Nature Portfolio. It was established as ''Nature Clinical Practice Nephrology'' in 2005, but change name in 2009. The editor-in-chief is Susan Allison. Coverage includes prevention, diagnosis, and treatment of disorders of the kidney in the adult and child, including hypertension, infection/inflammation, dialysis/chronic uremia, renal failure, transplantation, applied physiology, epidemiology, pathology, immunology, cancer, and genetics. Abstracting and indexing The journal is abstracted and indexed in: *PubMed/MEDLINE * Science Citation Index Expanded *Scopus According to the ''Journal Citation Reports'', the journal has a 2021 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a given journal, as ... of 4 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greek Mythology
A major branch of classical mythology, Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the Cosmogony, origin and Cosmology#Metaphysical cosmology, nature of the world, the lives and activities of List of Greek mythological figures, deities, Greek hero cult, heroes, and List of Greek mythological creatures, mythological creatures, and the origins and significance of the ancient Greeks' own cult (religious practice), cult and ritual practices. Modern scholars study the myths to shed light on the religious and political institutions of ancient Greece, and to better understand the nature of myth-making itself. The Greek myths were initially propagated in an oral tradition, oral-poetic tradition most likely by Minoan civilization, Minoan and Mycenaean Greece, Mycenaean singers starting in the 18th century BC; eventually the myths of the heroes of the Trojan War and its after ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moirai
In ancient Greek religion and mythology, the Moirai (, also spelled Moirae or Mœræ; grc, Μοῖραι, "lots, destinies, apportioners"), often known in English as the Fates ( la, Fata, Fata, -orum (n)=), were the personifications of fate; their Roman equivalent was the Parcae (euphemistically the "sparing ones"), and there are other equivalents in cultures that descend from the Proto-Indo-European culture. Their number became fixed at three: Clotho ("spinner"), Lachesis ("allotter") and Atropos ("the unturnable", a metaphor for death). However, according to the often cited Latin verse ''Clotho colum retinet, Lachesis net, et Atropos occat'', their roles and functions were also seen differently: Clotho, the youngest of the sisters, presided over the moment in which we are born, and held a distaff in her hand; Lachesis spun out all the events and actions of our life; and Atropos, the eldest of the three, cut the thread of human life with a pair of scissors. The role of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clotho
Clotho (; el, Κλωθώ) is a mythological figure. She is the youngest of the Three Fates or Moirai who spins the thread of human life; the other two draw out (Lachesis) and cut (Atropos) in ancient Greek mythology. Her Roman equivalent is Nona. She also made major decisions, such as when a person was born, thus in effect controlling people's lives. This power enabled her not only to choose who was born, but also to decide when gods or mortals were to be saved or put to death. For example, Clotho brought Pelops back to life when his father killed him. As one of the three fates her impact on Greek mythology was significant. Clotho, along with her sisters and Hermes, was given credit for creating the alphabet for their people. Even though Clotho and her sisters were worshiped as goddesses, their representation of fate is more central to their role in mythology. Thread represented human life and her decisions represented the fate of all people in society. Origin According to H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ageing
Ageing ( BE) or aging ( AE) is the process of becoming older. The term refers mainly to humans, many other animals, and fungi, whereas for example, bacteria, perennial plants and some simple animals are potentially biologically immortal. In a broader sense, ageing can refer to single cells within an organism which have ceased dividing, or to the population of a species. In humans, ageing represents the accumulation of changes in a human being over time and can encompass physical, psychological, and social changes. Reaction time, for example, may slow with age, while memories and general knowledge typically increase. Ageing increases the risk of human diseases such as cancer, Alzheimer's disease, diabetes, cardiovascular disease, stroke and many more. Of the roughly 150,000 people who die each day across the globe, about two-thirds die from age-related causes. Current ageing theories are assigned to the damage concept, whereby the accumulation of damage (such as DNA ox ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Insulin
Insulin (, from Latin ''insula'', 'island') is a peptide hormone produced by beta cells of the pancreatic islets encoded in humans by the ''INS'' gene. It is considered to be the main anabolic hormone of the body. It regulates the metabolism of carbohydrates, fats and protein by promoting the absorption of glucose from the blood into liver, fat and skeletal muscle cells. In these tissues the absorbed glucose is converted into either glycogen via glycogenesis or fats (triglycerides) via lipogenesis, or, in the case of the liver, into both. Glucose production and secretion by the liver is strongly inhibited by high concentrations of insulin in the blood. Circulating insulin also affects the synthesis of proteins in a wide variety of tissues. It is therefore an anabolic hormone, promoting the conversion of small molecules in the blood into large molecules inside the cells. Low insulin levels in the blood have the opposite effect by promoting widespread catabolism, especially o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
