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CA1 (gene)
Carbonic anhydrase 1 is an enzyme that in humans is encoded by the ''CA1'' gene. Carbonic anhydrases (CAs) are a large family of zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide. They participate in a variety of biological processes, including cellular respiration, calcification, acid-base balance, bone resorption, and the formation of aqueous humor, cerebrospinal fluid, saliva, and gastric acid. They show extensive diversity in tissue distribution and in their subcellular localization. CA1 is closely linked to CA2 and CA3 genes on chromosome 8, and it encodes a cytosolic protein which is found at the highest level in erythrocytes. Transcript variants of CA1 utilizing alternative polyA_sites have been described in literature. Structure The human CA1 protein contains an N-terminus active site, zinc binding site, and substrate-binding site. The crystal structure of the human CA1-bicarbonate anion complex reveals the geometry of two H-bonds between ... [...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 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 are Ribozyme, catalytic RNA molecules, called ribozymes. Enzymes' Chemical specificity, specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Threonine
Threonine (symbol Thr or T) is an amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH form under biological conditions), a carboxyl group (which is in the deprotonated −COO− form under biological conditions), and a side chain containing a hydroxyl group, making it a polar, uncharged amino acid. It is essential in humans, meaning the body cannot synthesize it: it must be obtained from the diet. Threonine is synthesized from aspartate in bacteria such as ''E. coli''. It is encoded by all the codons starting AC (ACU, ACC, ACA, and ACG). Threonine sidechains are often hydrogen bonded; the most common small motifs formed are based on interactions with serine: ST turns, ST motifs (often at the beginning of alpha helices) and ST staples (usually at the middle of alpha helices). Modifications The threonine residue is susceptible to numerous posttranslational modifications. The hydroxyl side-chain can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Blood Cell
Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "hollow vessel", with ''-cyte'' translated as "cell" in modern usage), are the most common type of blood cell and the vertebrate's principal means of delivering oxygen (O2) to the body tissues—via blood flow through the circulatory system. RBCs 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, 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 phys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytosol
The cytosol, also known as cytoplasmic matrix or groundplasm, is one of the liquids found inside cells ( intracellular fluid (ICF)). It is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondrion into many compartments. In the eukaryotic cell, the cytosol is surrounded by the cell membrane and is part of the cytoplasm, which also comprises the mitochondria, plastids, and other organelles (but not their internal fluids and structures); the cell nucleus is separate. The cytosol is thus a liquid matrix around the organelles. In prokaryotes, most of the chemical reactions of metabolism take place in the cytosol, while a few take place in membranes or in the periplasmic space. In eukaryotes, while many metabolic pathways still occur in the cytosol, others take place within organelles. The cytosol is a complex mixture of substances dissolved in water. Although water forms the large majority of the cytosol, its structure and prop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isozyme
In biochemistry, isozymes (also known as isoenzymes or more generally as multiple forms of enzymes) are enzymes that differ in amino acid sequence but catalyze the same chemical reaction. Isozymes usually have different kinetic parameters (e.g. different ''K''M values), or are regulated differently. They permit the fine-tuning of metabolism to meet the particular needs of a given tissue or developmental stage. In many cases, isozymes are encoded by homologous genes that have diverged over time. Strictly speaking, enzymes with different amino acid sequences that catalyse the same reaction are isozymes if encoded by different genes, or allozymes if encoded by different alleles of the same gene; the two terms are often used interchangeably. Introduction Isozymes were first described by R. L. Hunter and Clement Markert (1957) who defined them as ''different variants of the same enzyme having identical functions and present in the same individual''. This definition encompasses (1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalytic Efficiency
In the field of biochemistry, the specificity constant (also called kinetic efficiency or k_/K_), is a measure of how efficiently an enzyme converts substrates into products. A comparison of specificity constants can also be used as a measure of the preference of an enzyme for different substrates (i.e., substrate specificity). The higher the specificity constant, the more the enzyme "prefers" that substrate. The following equation, known as the Michaelis–Menten model, is used to describe the kinetics of enzymes: : + S _fk_r] ES -> _ + P where E, S, ES, and P represent enzyme, substrate, enzyme–substrate complex, and product, respectively. The symbols k_f, k_r, and k_\mathrm denote the rate constants for the "forward" binding and "reverse" unbinding of substrate, and for the "catalytic" conversion of substrate into product, respectively. The Michaelis constant in turn is defined as follows: : K_ = \frac The Michaelis constant is equal to the substrate concentration a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turnover Number
Turnover number has two different meanings: In enzymology, turnover number (also termed ''k''cat) is defined as the maximum number of chemical conversions of substrate molecules per second that a single active site will execute for a given enzyme concentration _T/math> for enzymes with two or more active sites. For enzymes with a single active site, ''k''cat is referred to as the catalytic constant. It can be calculated from the maximum reaction rate V_\max and catalyst site concentration _T/math> as follows: :k_\mathrm = \frac (See Michaelis–Menten kinetics). In other chemical fields, such as organometallic catalysis, turnover number (abbreviated ''TON'') has a different meaning: the number of moles of substrate that a mole of catalyst can convert before becoming inactivated. An ideal catalyst would have an infinite turnover number in this sense, because it would never be consumed. The term turnover frequency (abbreviated ''TOF'') is used to refer to the turnover per unit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michaelis Constant
Michaelis or Michelis is a surname. Notable people and characters with the surname include: * Adolf Michaelis, German classical scholar * Anthony R. Michaelis, German science writer * Edward Michelis, German theologian * Georg Michaelis, German politician * Gustav Adolf Michaelis, German obstetrician and namesake of the rhombus of Michaelis * Hans-Thorald Michaelis, German historian * Johann David Michaelis, German biblical scholar * John H. Michaelis, American four-star general * Laura Michaelis, American linguist * Leo Michelis, Greek-Canadian economist * Leonor Michaelis, German scientist known for Michaelis–Menten kinetics * Max Michaelis, South African financier * Margaret Michaelis-Sachs, Austrian-Australian photographer * Paul Charles Michaelis, American scientist * Peter Michaelis, German botanist * Robert Michaelis (1878–1965), French-born actor and singer who settled in England * Sebastian Michaelis, the demon butler from Kuroshitsuji * Sebastien Michaelis, Fre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Tissue
In biology, tissue is a biological organizational level between cells and a complete organ. A tissue is an ensemble of similar cells and their extracellular matrix from the same origin that together carry out a specific function. Organs are then formed by the functional grouping together of multiple tissues. The English word "tissue" derives from the French word "tissu", the past participle of the verb tisser, "to weave". The study of tissues is known as histology or, in connection with disease, as histopathology. Xavier Bichat is considered as the "Father of Histology". Plant histology is studied in both plant anatomy and physiology. The classical tools for studying tissues are the paraffin block in which tissue is embedded and then sectioned, the histological stain, and the optical microscope. Developments in electron microscopy, immunofluorescence, and the use of frozen tissue-sections have enhanced the detail that can be observed in tissues. With these tools, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anions
An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convention. The net charge of an ion is not zero because its total number of electrons is unequal to its total number of protons. A cation is a positively charged ion with fewer electrons than protons while an anion is a negatively charged ion with more electrons than protons. Opposite electric charges are pulled towards one another by electrostatic force, so cations and anions attract each other and readily form ionic compounds. Ions consisting of only a single atom are termed atomic or monatomic ions, while two or more atoms form molecular ions or polyatomic ions. In the case of physical ionization in a fluid (gas or liquid), "ion pairs" are created by spontaneous molecule collisions, where each generated pair consists of a free electron a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Product Inhibition
Product inhibition is a type of enzyme inhibition where the product of an enzyme reaction inhibits its production. Cells utilize product inhibition to regulate of metabolism as a form of negative feedback controlling metabolic pathways. Product inhibition is also an important topic in biotechnology, as overcoming this effect can increase the yield of a product, such as an antibiotic. Product inhibition can be Competitive, non-competitive or uncompetitive. Mitigation of product inhibition Reactor Design One method to reduce product inhibition is the use of a membrane reactor. These bioreactors uses a membrane to separate products from the rest of the reactor, limiting their inhibition. If the product differs greatly in size from the cells producing it, and the substrate feeding the cells, then the reactor can utilize a semipermeable membrane allowing to products to exit the reactor while leaving the cells and substrate behind to continue reacting making more product. Other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
