Hydrocarbons
Hydrocarbons are organic compounds consisting entirely of hydrogen and carbon atoms, forming the basis of classes such as alkanes, alkenes, alkynes, and aromatic hydrocarbons, which play a vital role in energy production and chemical synthesis.
Hydrocarbons, Aromatic
Organic compounds containing carbon and hydrogen in the form of an unsaturated, usually hexagonal ring structure. The compounds can be single ring, or double, triple, or multiple fused rings.
Receptors, Aryl Hydrocarbon
Cytoplasmic proteins that bind certain aryl hydrocarbons, translocate to the nucleus, and activate transcription of particular DNA segments. AH receptors are identified by their high-affinity binding to several carcinogenic or teratogenic environmental chemicals including polycyclic aromatic hydrocarbons found in cigarette smoke and smog, heterocyclic amines found in cooked foods, and halogenated hydrocarbons including dioxins and polychlorinated biphenyls. No endogenous ligand has been identified, but an unknown natural messenger with a role in cell differentiation and development is suspected.
Polycyclic Hydrocarbons, Aromatic
A major group of unsaturated cyclic hydrocarbons containing two or more rings. The vast number of compounds of this important group, derived chiefly from petroleum and coal tar, are rather highly reactive and chemically versatile. The name is due to the strong and not unpleasant odor characteristic of most substances of this nature. (From Hawley's Condensed Chemical Dictionary, 12th ed, p96)
Tetrachlorodibenzodioxin
A chemical by-product that results from burning or incinerating chlorinated industrial chemicals and other hydrocarbons. This compound is considered an environmental toxin, and may pose reproductive, as well as, other health risks for animals and humans.
Hydrocarbons, Halogenated
Halogenated hydrocarbons refer to organic compounds containing carbon and hydrogen atoms, where one or more hydrogen atoms are replaced by halogens such as fluorine, chlorine, bromine, or iodine.
Benzo(a)pyrene
A potent mutagen and carcinogen. It is a public health concern because of its possible effects on industrial workers, as an environmental pollutant, an as a component of tobacco smoke.
Cytochrome P-450 CYP1A1
A liver microsomal cytochrome P-450 monooxygenase capable of biotransforming xenobiotics such as polycyclic hydrocarbons and halogenated aromatic hydrocarbons into carcinogenic or mutagenic compounds. They have been found in mammals and fish. This enzyme, encoded by CYP1A1 gene, can be measured by using ethoxyresorufin as a substrate for the ethoxyresorufin O-deethylase activity.
Aryl Hydrocarbon Receptor Nuclear Translocator
Aryl hydrocarbon receptor nuclear translocator is a basic HELIX-LOOP-HELIX MOTIF containing protein that forms a complex with DIOXIN RECEPTOR. The complex binds xenobiotic regulatory elements and activates transcription of a variety of genes including UDP GLUCURONOSYLTRANSFERASE. AhR nuclear translocator is also a subunit of HYPOXIA-INDUCIBLE FACTOR 1.
Pyrenes
A group of condensed ring hydrocarbons.
Hydrocarbons, Chlorinated
Biodegradation, Environmental
Elimination of ENVIRONMENTAL POLLUTANTS; PESTICIDES and other waste using living organisms, usually involving intervention of environmental or sanitation engineers.
Benz(a)Anthracenes
Aryl Hydrocarbon Hydroxylases
A large group of cytochrome P-450 (heme-thiolate) monooxygenases that complex with NAD(P)H-FLAVIN OXIDOREDUCTASE in numerous mixed-function oxidations of aromatic compounds. They catalyze hydroxylation of a broad spectrum of substrates and are important in the metabolism of steroids, drugs, and toxins such as PHENOBARBITAL, carcinogens, and insecticides.
Petroleum
Naturally occurring complex liquid hydrocarbons which, after distillation, yield combustible fuels, petrochemicals, and lubricants.
Alkanes
The generic name for the group of aliphatic hydrocarbons Cn-H2n+2. They are denoted by the suffix -ane. (Grant & Hackh's Chemical Dictionary, 5th ed)
Benzopyrenes
Soil Pollutants
Substances which pollute the soil. Use for soil pollutants in general or for which there is no specific heading.
Dioxins
Chlorinated hydrocarbons containing heteroatoms that are present as contaminants of herbicides. Dioxins are carcinogenic, teratogenic, and mutagenic. They have been banned from use by the FDA.
Phenanthrenes
Phenanthrenes are aromatic hydrocarbons consisting of three benzene rings fused together in a linear arrangement, commonly found in various plants and some animals, and can act as precursors for certain steroid hormones or exhibit pharmacological activities with potential therapeutic uses.
DNA Adducts
The products of chemical reactions that result in the addition of extraneous chemical groups to DNA.
Environmental Pollutants
Substances or energies, for example heat or light, which when introduced into the air, water, or land threaten life or health of individuals or ECOSYSTEMS.
Carcinogens
Substances that increase the risk of NEOPLASMS in humans or animals. Both genotoxic chemicals, which affect DNA directly, and nongenotoxic chemicals, which induce neoplasms by other mechanism, are included.
Hydrocarbons, Alicyclic
Water Pollutants, Chemical
Fuel Oils
Complex petroleum hydrocarbons consisting mainly of residues from crude oil distillation. These liquid products include heating oils, stove oils, and furnace oils and are burned to generate energy.
Chrysenes
Benzene Derivatives
Environmental Monitoring
The monitoring of the level of toxins, chemical pollutants, microbial contaminants, or other harmful substances in the environment (soil, air, and water), workplace, or in the bodies of people and animals present in that environment.
Coal Tar
A by-product of the destructive distillation of coal used as a topical antieczematic. It is an antipruritic and keratoplastic agent used also in the treatment of psoriasis and other skin conditions. Occupational exposure to soots, tars, and certain mineral oils is known to be carcinogenic according to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985) (Merck Index, 11th ed).
Coke
A residue of coal, left after dry (destructive) distillation, used as a fuel.
Creosote
A greasy substance with a smoky odor and burned taste created by high temperature treatment of BEECH and other WOOD; COAL TAR; or resin of the CREOSOTE BUSH. It contains CRESOLS and POLYCYCLIC AROMATIC HYDROCARBONS which are CARCINOGENS. It has been widely used as wood preservative and in PESTICIDES and had former use medicinally in DISINFECTANTS; LAXATIVES; and DERMATOLOGIC AGENTS.
Gasoline
Volative flammable fuel (liquid hydrocarbons) derived from crude petroleum by processes such as distillation reforming, polymerization, etc.
Bay-Region, Polycyclic Aromatic Hydrocarbon
A concave exterior region on some POLYCYCLIC AROMATIC HYDROCARBONS that have three phenyl rings in a non-linear arrangement.
Xylenes
A family of isomeric, colorless aromatic hydrocarbon liquids, that contain the general formula C6H4(CH3)2. They are produced by the destructive distillation of coal or by the catalytic reforming of petroleum naphthenic fractions. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)
Biotransformation
The chemical alteration of an exogenous substance by or in a biological system. The alteration may inactivate the compound or it may result in the production of an active metabolite of an inactive parent compound. The alterations may be divided into METABOLIC DETOXICATION, PHASE I and METABOLIC DETOXICATION, PHASE II.
Hydrocarbons, Acyclic
Gas Chromatography-Mass Spectrometry
A microanalytical technique combining mass spectrometry and gas chromatography for the qualitative as well as quantitative determinations of compounds.
Acenaphthenes
Polychlorinated Biphenyls
Industrial products consisting of a mixture of chlorinated biphenyl congeners and isomers. These compounds are highly lipophilic and tend to accumulate in fat stores of animals. Many of these compounds are considered toxic and potential environmental pollutants.
Benzene
Toxic, volatile, flammable liquid hydrocarbon byproduct of coal distillation. It is used as an industrial solvent in paints, varnishes, lacquer thinners, gasoline, etc. Benzene causes central nervous system damage acutely and bone marrow damage chronically and is carcinogenic. It was formerly used as parasiticide.
Enzyme Induction
Air Pollutants
Any substance in the air which could, if present in high enough concentration, harm humans, animals, vegetation or material. Substances include GASES; PARTICULATE MATTER; and volatile ORGANIC CHEMICALS.
7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide
Mutagens
Chemical agents that increase the rate of genetic mutation by interfering with the function of nucleic acids. A clastogen is a specific mutagen that causes breaks in chromosomes.
Alkenes
Unsaturated hydrocarbons of the type Cn-H2n, indicated by the suffix -ene. (Grant & Hackh's Chemical Dictionary, 5th ed, p408)
Molecular Sequence Data
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Molecular Structure
beta-Naphthoflavone
Cytochrome P-450 Enzyme System
A superfamily of hundreds of closely related HEMEPROTEINS found throughout the phylogenetic spectrum, from animals, plants, fungi, to bacteria. They include numerous complex monooxygenases (MIXED FUNCTION OXYGENASES). In animals, these P-450 enzymes serve two major functions: (1) biosynthesis of steroids, fatty acids, and bile acids; (2) metabolism of endogenous and a wide variety of exogenous substrates, such as toxins and drugs (BIOTRANSFORMATION). They are classified, according to their sequence similarities rather than functions, into CYP gene families (>40% homology) and subfamilies (>59% homology). For example, enzymes from the CYP1, CYP2, and CYP3 gene families are responsible for most drug metabolism.
Structure-Activity Relationship
Phenylalanine
Oxygenases
Naphthalenes
Two-ring crystalline hydrocarbons isolated from coal tar. They are used as intermediates in chemical synthesis, as insect repellents, fungicides, lubricants, preservatives, and, formerly, as topical antiseptics.
Air Pollutants, Occupational
Benzoflavones
Organic compounds containing a BENZENE ring attached to a flavone group. Some of these are potent arylhydrocarbon hydroxylase inhibitors. They may also inhibit the binding of NUCLEIC ACIDS to BENZOPYRENES and related compounds. The designation includes all isomers; the 7,8-isomer is most frequently encountered.
Occupational Exposure
Soil Microbiology
The presence of bacteria, viruses, and fungi in the soil. This term is not restricted to pathogenic organisms.
Amines
Models, Molecular
Vehicle Emissions
Gases, fumes, vapors, and odors escaping from the cylinders of a gasoline or diesel internal-combustion engine. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed & Random House Unabridged Dictionary, 2d ed)
Xenobiotics
Chemical substances that are foreign to the biological system. They include naturally occurring compounds, drugs, environmental agents, carcinogens, insecticides, etc.
Chromatography, Gas
Fractionation of a vaporized sample as a consequence of partition between a mobile gaseous phase and a stationary phase held in a column. Two types are gas-solid chromatography, where the fixed phase is a solid, and gas-liquid, in which the stationary phase is a nonvolatile liquid supported on an inert solid matrix.
Magnetic Resonance Spectroscopy
Tryptophan
An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals.
9,10-Dimethyl-1,2-benzanthracene
7,12-Dimethylbenzanthracene. Polycyclic aromatic hydrocarbon found in tobacco smoke that is a potent carcinogen.
Geologic Sediments
A mass of organic or inorganic solid fragmented material, or the solid fragment itself, that comes from the weathering of rock and is carried by, suspended in, or dropped by air, water, or ice. It refers also to a mass that is accumulated by any other natural agent and that forms in layers on the earth's surface, such as sand, gravel, silt, mud, fill, or loess. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1689)
Kerosene
A refined petroleum fraction used as a fuel as well as a solvent.
Gulf of Mexico
A body of water located at the southeastern corner of North America. It is bordered by the states to the north of Florida, Alabama, Mississippi, Louisiana, Texas; by five Mexican states to the west: Tamaulipas, Veracruz, Tabasco, Campeche, Yucatan; and by Cuba to the southeast.
Benzopyrene Hydroxylase
A drug-metabolizing, cytochrome P-448 (P-450) enzyme which catalyzes the hydroxylation of benzopyrene to 3-hydroxybenzopyrene in the presence of reduced flavoprotein and molecular oxygen. Also acts on certain anthracene derivatives. An aspect of EC 1.14.14.1.
Dioxygenases
Non-heme iron-containing enzymes that incorporate two atoms of OXYGEN into the substrate. They are important in biosynthesis of FLAVONOIDS; GIBBERELLINS; and HYOSCYAMINE; and for degradation of AROMATIC HYDROCARBONS.
Cytochrome P-450 CYP1A2
Amino Acid Sequence
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Pseudomonas putida
Coal
Mutagenicity Tests
Water Pollution, Chemical
Adverse effect upon bodies of water (LAKES; RIVERS; seas; groundwater etc.) caused by CHEMICAL WATER POLLUTANTS.
Integumentary System
Stereoisomerism
Environmental Exposure
Pseudomonas
A genus of gram-negative, aerobic, rod-shaped bacteria widely distributed in nature. Some species are pathogenic for humans, animals, and plants.
Solvents
Liquids that dissolve other substances (solutes), generally solids, without any change in chemical composition, as, water containing sugar. (Grant & Hackh's Chemical Dictionary, 5th ed)
Ketones
Oil and Gas Fields
Areas of the earth where hydrocarbon deposits of PETROLEUM and/or NATURAL GAS are located.
Dihydroxydihydrobenzopyrenes
Oxidation-Reduction
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
Bacteria
One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.
Binding Sites
Chromatography, High Pressure Liquid
Substrate Specificity
Propane
Propane is a colorless, odorless, and chemically simple hydrocarbon (C3H8), commonly used as a fuel for heating, cooking, and engines, which exists as a gas at room temperature but can be liquefied under pressure and stored in cylinders or tanks.
Octanes
Eight-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives.
Liver
Mixed Function Oxygenases
Widely distributed enzymes that carry out oxidation-reduction reactions in which one atom of the oxygen molecule is incorporated into the organic substrate; the other oxygen atom is reduced and combined with hydrogen ions to form water. They are also known as monooxygenases or hydroxylases. These reactions require two substrates as reductants for each of the two oxygen atoms. There are different classes of monooxygenases depending on the type of hydrogen-providing cosubstrate (COENZYMES) required in the mixed-function oxidation.
Mineral Oil
A mixture of liquid hydrocarbons obtained from petroleum. It is used as laxative, lubricant, ointment base, and emollient.
Shikimic Acid
Particulate Matter
Benzoates
Derivatives of BENZOIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxybenzene structure.
Naphthols
Hydroxybenzoates
Benzoate derivatives substituted by one or more hydroxy groups in any position on the benzene ring.
Sphingomonas
A genus of gram-negative, aerobic, rod-shaped bacteria characterized by an outer membrane that contains glycosphingolipids but lacks lipopolysaccharide. They have the ability to degrade a broad range of substituted aromatic compounds.
Butanes
Hydrocarbons, Cyclic
Organic compounds composed exclusively of carbon and hydrogen forming a closed ring that may be either alicyclic or aromatic.
Epoxy Compounds
Lipid Bilayers
Ligands
A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)
Sex Attractants
Ethane
Ethane is an organic compound, specifically a hydrocarbon (aliphatic alkane), with the chemical formula C2H6, which consists of two carbon atoms and six hydrogen atoms, and is the second simplest alkane after methane. However, it's important to note that ethane is not a medical term or concept; it's a basic chemistry term.
Protein Conformation
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
Models, Chemical
Protein Binding
Fundulidae
Microsomes, Liver
Closed vesicles of fragmented endoplasmic reticulum created when liver cells or tissue are disrupted by homogenization. They may be smooth or rough.
Water Pollutants
Substances or organisms which pollute the water or bodies of water. Use for water pollutants in general or those for which there is no specific heading.
Hydroxylation
Metabolic Detoxication, Drug
Metallurgy
The science, art, or technology dealing with processes involved in the separation of metals from their ores, the technique of making or compounding the alloys, the techniques of working or heat-treating metals, and the mining of metals. It includes industrial metallurgy as well as metallurgical techniques employed in the preparation and working of metals used in dentistry, with special reference to orthodontic and prosthodontic appliances. (From Jablonski, Dictionary of Dentistry, 1992, p494)
Base Sequence
Catalysis
Volatile Organic Compounds
Organic compounds that have a relatively high VAPOR PRESSURE at room temperature.
Water
Incineration
High temperature destruction of waste by burning with subsequent reduction to ashes or conversion to an inert mass.
Glutathione Transferase
Inhalation Exposure
Cooking
Smoke
Temperature
The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.
Water Microbiology
Oils, Volatile
Oils which evaporate readily. The volatile oils occur in aromatic plants, to which they give odor and other characteristics. Most volatile oils consist of a mixture of two or more TERPENES or of a mixture of an eleoptene (the more volatile constituent of a volatile oil) with a stearopten (the more solid constituent). The synonym essential oils refers to the essence of a plant, as its perfume or scent, and not to its indispensability.
Benzofurans
Compounds that contain a BENZENE ring fused to a furan ring.
Environmental Pollution
Contamination of the air, bodies of water, or land with substances that are harmful to human health and the environment.
Seawater
The salinated water of OCEANS AND SEAS that provides habitat for marine organisms.
Heterocyclic Compounds
Ring compounds having atoms other than carbon in their nuclei. (Grant & Hackh's Chemical Dictionary, 5th ed)
Thermodynamics
A rigorously mathematical analysis of energy relationships (heat, work, temperature, and equilibrium). It describes systems whose states are determined by thermal parameters, such as temperature, in addition to mechanical and electromagnetic parameters. (From Hawley's Condensed Chemical Dictionary, 12th ed)
Parabens
Methyl, propyl, butyl, and ethyl esters of p-hydroxybenzoic acid. They have been approved by the FDA as antimicrobial agents for foods and pharmaceuticals. (From Hawley's Condensed Chemical Dictionary, 11th ed, p872)
Amino Acids
DNA
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
Volatilization
Mutation
Fossil Fuels
Species Specificity
The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.
Nitro Compounds
Compounds having the nitro group, -NO2, attached to carbon. When attached to nitrogen they are nitramines and attached to oxygen they are NITRATES.
Organic Chemicals
Tyrosine
A non-essential amino acid. In animals it is synthesized from PHENYLALANINE. It is also the precursor of EPINEPHRINE; THYROID HORMONES; and melanin.
Methane
The simplest saturated hydrocarbon. It is a colorless, flammable gas, slightly soluble in water. It is one of the chief constituents of natural gas and is formed in the decomposition of organic matter. (Grant & Hackh's Chemical Dictionary, 5th ed)
RNA, Messenger
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
Carbon
Trichloroethylene
Hazardous Waste
Dose-Response Relationship, Drug
Crystallography, X-Ray
The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Hexanes
Six-carbon saturated hydrocarbon group of the methane series. Include isomers and derivatives. Various polyneuropathies are caused by hexane poisoning.
Toluidines
Toluidines are a group of organic compounds consisting of various derivatives of toluene with an amine group (-NH2) attached to the benzene ring, which have been used in chemical synthesis and historical medical research but are not currently utilized as therapeutic agents due to their carcinogenic properties.
Hydrophobic and Hydrophilic Interactions
The thermodynamic interaction between a substance and WATER.
Basic Helix-Loop-Helix Transcription Factors
X-Ray Diffraction
The scattering of x-rays by matter, especially crystals, with accompanying variation in intensity due to interference effects. Analysis of the crystal structure of materials is performed by passing x-rays through them and registering the diffraction image of the rays (CRYSTALLOGRAPHY, X-RAY). (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
RNA, Ribosomal, 16S
Biofuels
Hydrocarbon-rich byproducts from the non-fossilized BIOMASS that are combusted to generate energy as opposed to fossilized hydrocarbon deposits (FOSSIL FUELS).
Ants
Insects of the family Formicidae, very common and widespread, probably the most successful of all the insect groups. All ants are social insects, and most colonies contain three castes, queens, males, and workers. Their habits are often very elaborate and a great many studies have been made of ant behavior. Ants produce a number of secretions that function in offense, defense, and communication. (From Borror, et al., An Introduction to the Study of Insects, 4th ed, p676)
Sequence Analysis, DNA
A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.
Chemistry
Oxidoreductases
The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)
Sequence Homology, Amino Acid
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Surface-Active Agents
Agents that modify interfacial tension of water; usually substances that have one lipophilic and one hydrophilic group in the molecule; includes soaps, detergents, emulsifiers, dispersing and wetting agents, and several groups of antiseptics.
Chromatography, Thin Layer
Extraction and Processing Industry
Esters
Escherichia coli
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
Cyclization
7-Alkoxycoumarin O-Dealkylase
Spectrophotometry, Ultraviolet
Mass Spectrometry
Solid Phase Microextraction
Pheromones
Chemical Phenomena
Epoxide Hydrolases
Quinones
Protein Structure, Secondary
The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.
Hydrogen Bonding
A low-energy attractive force between hydrogen and another element. It plays a major role in determining the properties of water, proteins, and other compounds.
3-Deoxy-7-Phosphoheptulonate Synthase
An enzyme that catalyzes the formation of 7-phospho-2-keto-3-deoxy-D-arabinoheptonate from phosphoenolpyruvate and D-erythrose-4-phosphate. It is one of the first enzymes in the biosynthesis of TYROSINE and PHENYLALANINE. This enzyme was formerly listed as EC 4.1.2.15.
Mutagenesis, Site-Directed
Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.
Cresols
Cresols, also known as hydroxytoluene, are a group of phenolic compounds including ortho-cresol, meta-cresol, and para-cresol, which differ in the position of the hydroxyl group on the benzene ring.