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DBT (gene)
Lipoamide acyltransferase component of branched-chain alpha-keto acid dehydrogenase complex, mitochondrial is an enzyme that in humans is encoded by the ''DBT'' gene. The branched-chain alpha-keto acid dehydrogenase complex (BCKD) is an inner-mitochondrial enzyme complex involved in the breakdown of the branched-chain amino acids isoleucine, leucine, and valine. The BCKD complex is thought to be composed of a core of 24 transacylase (E2) subunits, and associated decarboxylase (E1), dehydrogenase (E3), and regulatory subunits. This gene encodes the transacylase (E2) subunit. Mutations in this gene result in maple syrup urine disease, type 2. Alternatively spliced transcript variants Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process, particular exons of a gene may be ... have been described, but their biological validit ... [...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] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Branched-chain Alpha-keto Acid Dehydrogenase Complex
The branched-chain α-ketoacid dehydrogenase complex (BCKDC or BCKDH complex) is a multi-subunit complex of enzymes that is found on the mitochondrial inner membrane. This enzyme complex catalyzes the oxidative decarboxylation of branched, short-chain alpha-ketoacids. BCKDC is a member of the mitochondrial α-ketoacid dehydrogenase complex family comprising pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase, key enzymes that function in the Krebs cycle. Coenzymes This complex requires the following 5 coenzymes: *Thiamine pyrophosphate *Lipoic acid, Lipoate (lipoic acid) *Coenzyme A *Flavin adenine dinucleotide (FAD) *Nicotinamide adenine dinucleotide (NAD+) Biological function In animal tissue, BCKDC catalyzes an irreversible step in the catabolism of the branched-chain amino acids L-isoleucine, L-valine, and L-leucine, acting on their deaminated derivatives (L-alpha-keto-beta-methylvalerate, alpha-ketoisovalerate, and alpha-ketoisocaproate, respectively) and converting t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inner Mitochondrial Membrane
The inner mitochondrial membrane (IMM) is the mitochondrial membrane which separates the mitochondrial matrix from the intermembrane space. Structure The structure of the inner mitochondrial membrane is extensively folded and compartmentalized. The numerous invaginations of the membrane are called cristae, separated by crista junctions from the inner boundary membrane juxtaposed to the outer membrane. Cristae significantly increase the total membrane surface area compared to a smooth inner membrane and thereby the available working space for oxidative phosphorylation. The inner membrane creates two compartments. The region between the inner and outer membrane, called the intermembrane space, is largely continuous with the cytosol, while the more sequestered space inside the inner membrane is called the matrix. Cristae For typical liver mitochondria, the area of the inner membrane is about 5 times as large as the outer membrane due to cristae. This ratio is variable and mitocho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isoleucine
Isoleucine (symbol Ile or I) is an α-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), an α-carboxylic acid group (which is in the deprotonated −COO form under biological conditions), and a hydrocarbon side chain with a branch (a central carbon atom bound to three other carbon atoms). It is classified as a non-polar, uncharged (at physiological pH), branched-chain, aliphatic amino acid. It is essential in humans, meaning the body cannot synthesize it, and must be ingested in our diet. Isoleucine is synthesized from pyruvate employing leucine biosynthesis enzymes in other organisms such as bacteria. It is encoded by the codons AUU, AUC, and AUA. Metabolism Biosynthesis As an essential nutrient, it is not synthesized in the body, hence it must be ingested, usually as a component of proteins. In plants and microorganisms, it is synthesized via several steps, startin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leucine
Leucine (symbol Leu or L) is an essential amino acid that is used in the biosynthesis of proteins. Leucine is an α-amino acid, meaning it contains an α-amino group (which is in the protonated −NH3+ form under biological conditions), an α- carboxylic acid group (which is in the deprotonated −COO− form under biological conditions), and a side chain isobutyl group, making it a non-polar aliphatic amino acid. It is essential in humans, meaning the body cannot synthesize it: it must be obtained from the diet. Human dietary sources are foods that contain protein, such as meats, dairy products, soy products, and beans and other legumes. It is encoded by the codons UUA, UUG, CUU, CUC, CUA, and CUG. Like valine and isoleucine, leucine is a branched-chain amino acid. The primary metabolic end products of leucine metabolism are acetyl-CoA and acetoacetate; consequently, it is one of the two exclusively ketogenic amino acids, with lysine being the other. It is the most import ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valine
Valine (symbol Val or V) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH3+ form under biological conditions), an α- carboxylic acid group (which is in the deprotonated −COO− form under biological conditions), and a side chain isopropyl group, making it a non-polar aliphatic amino acid. It is essential in humans, meaning the body cannot synthesize it: it must be obtained from the diet. Human dietary sources are foods that contain protein, such as meats, dairy products, soy products, beans and legumes. It is encoded by all codons starting with GU (GUU, GUC, GUA, and GUG). History and etymology Valine was first isolated from casein in 1901 by Hermann Emil Fischer. The name valine comes from valeric acid, which in turn is named after the plant valerian due to the presence of the acid in the roots of the plant. Nomenclature According to IUPAC, carbon atoms forming valine are numbered sequentially s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transacylase
Acyltransferase is a type of transferase enzyme that acts upon acyl groups. Examples include: * Glyceronephosphate O-acyltransferase * Lecithin-cholesterol acyltransferase *Long-chain-alcohol O-fatty-acyltransferase In enzymology, a long-chain-alcohol O-fatty-acyltransferase () is an enzyme that catalyzes the chemical reaction :acyl-CoA + a long-chain alcohol \rightleftharpoons CoA + a long-chain ester Thus, the two substrates of this enzyme are acyl-C ... See also * Acetyltransferase External links * Transferases EC 2.3 {{2.3-enzyme-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decarboxylase
Carboxy-lyases, also known as decarboxylases, are carbon–carbon lyases that add or remove a carboxyl group from organic compounds. These enzymes catalyze the decarboxylation of amino acids, beta-keto acids and alpha-keto acids. Classification and nomenclature Carboxy-lyases are categorized under EC number 4.1.1. Usually, they are named after the substrate whose decarboxylation they catalyze, for example pyruvate decarboxylase catalyzes the decarboxylation of pyruvate. Examples * Aromatic-L-amino-acid decarboxylase * Glutamate decarboxylase * Histidine decarboxylase * Ornithine decarboxylase * Phosphoenolpyruvate carboxylase * Pyruvate decarboxylase * RuBisCO – the only carboxylase that leads to a net fixation of carbon dioxide * Uridine monophosphate synthetase * Uroporphyrinogen III decarboxylase * enoyl-CoA carboxylases/reductases (ECRs) See also * Enzymes * Lyase In biochemistry, a lyase is an enzyme that catalyzes the breaking (an elimination reaction) of various chem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dehydrogenase
A dehydrogenase is an enzyme belonging to the group of oxidoreductases that oxidizes a substrate by reducing an electron acceptor, usually NAD+/NADP+ or a flavin coenzyme such as FAD or FMN. Like all catalysts, they catalyze reverse as well as forward reactions, and in some cases this has physiological significance: for example, alcohol dehydrogenase catalyzes the oxidation of ethanol to acetaldehyde in animals, but in yeast it catalyzes the production of ethanol from acetaldehyde. IUBMB Classification Oxidoreductases, enzymes that catalyze oxidation-reduction reactions, constitute Class EC 1 of the IUBMB classification of enzyme-catalyzed reactions. Any of these may be called dehydrogenases, especially those in which NAD+ is the electron acceptor (oxidant), but reductase is also used when the physiological emphasis on reduction of the substrate, and oxidase is used ''only'' when O2 is the electron acceptor. The systematic name of an oxidoreductase is "donor:acceptor oxidore ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutations
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitosis, or meiosis or other types of damage to DNA (such as pyrimidine dimers caused by exposure to ultraviolet radiation), which then may undergo error-prone repair (especially microhomology-mediated end joining), cause an error during other forms of repair, or cause an error during replication (translesion synthesis). Mutations may also result from insertion or deletion of segments of DNA due to mobile genetic elements. Mutations may or may not produce detectable changes in the observable characteristics (phenotype) of an organism. Mutations play a part in both normal and abnormal biological processes including: evolution, cancer, and the development of the immune system, including junctional diversity. Mutation is the ultimate source o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maple Syrup Urine Disease
Maple syrup urine disease (MSUD) is an autosomal recessive metabolic disorder affecting branched-chain amino acids. It is one type of organic acidemia. The condition gets its name from the distinctive sweet odor of affected infants' urine and earwax, particularly prior to diagnosis and during times of acute illness. Signs and symptoms The disease is named for the presence of sweet-smelling urine, similar to maple syrup, when the person goes into metabolic crisis. The smell is also detected in ear wax of an affected individual during metabolic crisis. In populations to whom maple syrup is unfamiliar, the aroma can be likened to fenugreek, and fenugreek ingestion may impart the aroma to urine. Symptoms of MSUD varies between patients and is greatly related to the amount of residual enzyme activity. Classic MSUD Infants with classic MSUD will display subtle symptoms within the first 24–48 hours. Subtle symptoms include poor feeding, either bottle or breast, lethargy, and irrita ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
