Benzopyrene
Chemical name	Benzo[a]pyrene
Chemical formula	C20H12
Molecular mass	252.31 g/mol
CAS number	[50-32-8]
Density	1.24 g/cm³
Melting point	179 °C
Boiling point	495 °C
SMILES	c1cc2cc/cc3ccc4cc5ccccc5c1c4c23
Disclaimer and references

Benzo[a]pyrene, C₂₀H₁₂, is a five-ring polycyclic aromatic hydrocarbon that is mutagenic and highly carcinogenic. It is a crystalline yellow solid. Benzo[a]pyrene is a product of incomplete combustion at temperatures between 300 and 600 °C. Benzo[a]pyrene was determined in 1933 to be the component of coal tar responsible for the first recognized occupation-associated cancers, the sooty warts (cancers of the scrotum) suffered by chimney sweeps in 18th century England. In the 19th century, high incidences of skin cancers were noted among fuel industry workers. By the early 20th century, malignant skin tumors were produced in laboratory animals by repeatedly painting them with coal tar. Image File history File links No higher resolution available. ... IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ... A chemical formula (also called molecular formula) is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... The molecular mass (abbreviated MM) of a substance, formerly also called molecular weight and abbreviated as MW, is the mass of one molecule of that substance, relative to the unified atomic mass unit u (equal to 1/12 the mass of one atom of carbon-12). ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... In physics, density is defined as mass m per unit volume V. For the common case of a homogeneous substance, it is expressed as: where, in SI units: ρ (rho) is the density of the substance, measured in kg·m-3 m is the mass of the substance, measured in kg... The melting point of a crystalline solid is the temperature at which it changes state from solid to liquid. ... The boiling point of a substance is the temperature at which it can change its state from a liquid to a gas throughout the bulk of the liquid at a given pressure. ... The simplified molecular input line entry specification or SMILES is a specification for unambiguously describing the structure of chemical molecules using short ASCII strings. ... An illustration of typical polycyclic aromatic hydrocarbons - NASA Crystal structure of a hexa-peri-hexabenzocoronene reported by Müllen and cooworkers in Chem. ... In biology, a mutagen (Latin, literally origin of change) is a physical or chemical agent that changes the genetic information (usually DNA) of an organism and thus increases the number of mutations above the natural background level. ... The term carcinogen refers to any substance, radionuclide or radiation which is an agent directly involved in the promotion of cancer or in the facilitation of its propagation. ... Combustion or burning is a complex sequence of chemical reactions between a fuel and an oxidant accompanied by the production of heat or both heat and light in the form of either a glow or flames. ... Fig. ... Celsius is, or relates to, the Celsius temperature scale (previously known as the centigrade scale). ... Coal tar is the liquid by-product of the distillation of coal to make coke. ... For other uses, see Cancer (disambiguation). ... In some male mammals, the scrotum is a protuberance of skin and muscle containing the testicles. ... Chimney sweep in the 1850s A chimney sweep is a person who cleans chimneys for a living. ...

Benzo[a]pyrene is found in coal tar, in automobile exhaust fumes (especially from diesel engines), tobacco smoke, wood smoke, and in charbroiled food. Recent studies have revealed that levels of benzo[a]pyrene in burnt toast are significantly higher than once thought, although it is unproven whether burnt toast is itself carcinogenic. Coal tar is the liquid by-product of the distillation of coal to make coke. ... Rudolf Christian Karl Diesel (1858-1913), inventor of the diesel engine. ... Tobacco smoking is the act of smoking tobacco products, especially cigarettes and cigars. ... Smoke from a wildfire Smoke is a suspension in air (aerosol) of small particles resulting from incomplete combustion of a fuel. ... To charbroil is a means of cooking by placing meat, fish, or vegetables on a flat, horizontally-lined surface. ... Two slices of toasted white bread. ...

Consequences of Benzo[a]pyrene

Chemical structure of the carcinogen benzopyrene diol epoxide

A huge number of studies over the previous three decades have documented links between benzo[a]pyrene and cancers. It has been more difficult to link cancers to specific benzo[a]pyrene sources, especially in humans, and difficult to quantify risks posed by various methods of exposure (inhalation or ingestion). Researchers at Kansas State University recently discovered a link between vitamin A and emphysema in smokers^[1]. Benzo[a]pyrene was found to be the link to the deficiency, since it induces vitamin A deficiency in rats. Image File history File links Download high resolution version (1313x880, 7 KB) Description: Chemical structure of Benzopyrene diol epoxide. ... Image File history File links Download high resolution version (1313x880, 7 KB) Description: Chemical structure of Benzopyrene diol epoxide. ... Kansas State University, commonly shortened to K-State, is an institution of higher learning located in Manhattan, Kansas, in the United States. ... This article or section does not adequately cite its references or sources. ... This word has other meanings: see smoker. ...

In 1996, a study was published that provided the clear molecular evidence conclusively linking components in tobacco smoke to lung cancer.^[2] Benzo[a]pyrene, found in tobacco smoke, was shown to cause genetic damage in lung cells that was identical to the damage observed in the DNA of most malignant lung tumours. 1996 (MCMXCVI) was a leap year starting on Monday of the Gregorian calendar, and was designated the International Year for the Eradication of Poverty. ... Species Nicotiana acuminata Nicotiana alata Nicotiana attenuata Nicotiana benthamiana Nicotiana clevelandii Nicotiana excelsior Nicotiana forgetiana Nicotiana glauca Nicotiana glutinosa Nicotiana langsdorffii Nicotiana longiflora Nicotiana obtusifolia Nicotiana paniculata Nicotiana plumbagifolia Nicotiana quadrivalvis Nicotiana repanda Nicotiana rustica Nicotianasuaveolens Nicotiana sylvestris Nicotiana tabacum Nicotiana tomentosa Ref: ITIS 30562 as of August 26, 2005... Lung cancer is the malignant transformation and expansion of lung tissue, and is the most lethal of all cancers worldwide, responsible for 1. ... The structure of part of a DNA double helix Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the development and function of living organisms. ... Respiratory system The lungs flank the heart and great vessels in the chest cavity. ...

A 2001 National Cancer Institute study found levels of benzo[a]pyrene to be significantly higher in foods that were cooked well-done on the barbecue, particularly steaks, chicken with skin, and hamburgers^{[citation needed]}. Japanese scientists showed that cooked beef contains mutagens, chemicals that are capable of altering the chemical structure of DNA^{[citation needed]}. However, the foods themselves are not necessarily carcinogenic, even if they contain trace amounts of carcinogens, because the gastrointestinal tract protects itself against carcinomas by shedding its outer layer continuously. Furthermore, detoxification enzymes, such as cytochromes P450 have increased activities in the gut due to the normal requirement for protection from food-borne toxins. Thus in most cases small amounts of benzo[a]pyrene are metabolized by gut enzymes prior to being passed on to the blood. The lungs are not protected in either of these manners. 2001 (MMI) was a common year starting on Monday of the Gregorian calendar. ... The National Cancer Institute (NCI) is part of the United States Federal governments National Institutes of Health. ... It has been suggested that Grilling be merged into this article or section. ... A steak served with a pat of butter and mushrooms A steak is a slice from a larger piece of meat, typically beef. ... This article or section does not adequately cite its references or sources. ... For other uses, see Hamburger (disambiguation). ... For other uses, see Beef (disambiguation). ... The structure of part of a DNA double helix Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the development and function of living organisms. ... In medicine, carcinoma apanting dog named rufis It is malignant by definition: carcinomas invade surrounding tissues and organs, and may spread to lymph nodes and distal sites (metastasis). ... Cytochrome P450 Oxidase (CYP2E1) Cytochrome P450 oxidase (commonly abbreviated CYP) is a generic term for a large number of related, but distinct, oxidative enzymes (EC 1. ...

A recent study has found that cytochrome P450 1A1 (CYP1A1) and cytochrome P450 1B1 (CYP1B1) are both protective and, confusingly, necessary for benzo[a]pyrene toxicity. Experiments with strains of mice engineered to remove (knockout) CYP1A1and CYP1B1 reveal that CYP1A1 primarily acts to protect mammals from low doses of benzo[a]pyrene, and that removing this protection causes the biological accumulation of large concentrations of benzo[a]pyrene. Unless CYP1B1 is also knocked out, benzo[a]pyrene toxicity results from the bioactivation of benzo[a]pyrene to the ultimate toxic compound, benzo[a]pyrene diol epoxide (see below).^[3] Cytochrome P450 Oxidase (CYP2E1) Cytochrome P450 oxidase (commonly abbreviated CYP) is a generic term for a large number of related, but distinct, oxidative enzymes (EC 1. ... CYP1A1 is a gene that encodes a member of the cytochrome P450 oxidase superfamily of enzymes. ... Cytochrome P450 Oxidase (CYP2E1) Cytochrome P450 oxidase (commonly abbreviated CYP) is a generic term for a large number of related, but distinct, oxidative enzymes (EC 1. ... CYP1B1 belongs to a class of enzymes called Cytochrome P450 oxidases. ... A gene knockout is a genetically engineered organism that carries one or more genes in its chromosomes that has been made inoperative. ... CYP1A1 is a gene that encodes a member of the cytochrome P450 oxidase superfamily of enzymes. ... CYP1B1 belongs to a class of enzymes called Cytochrome P450 oxidases. ... CYP1B1 belongs to a class of enzymes called Cytochrome P450 oxidases. ...

Interaction with DNA

Benzopyrene, the major mutagen in tobacco smoke, in an adduct to DNA.^[4]

Properly speaking, benzo[a]pyrene is a procarcinogen, meaning that the mechanism of carcinogensis of benzo[a]pyrene depends on enzymatic metabolism of benzo[a]pyrene to the ultimate mutagen, benzo[a]pyrene diol epoxide. This molecule has a high druglikeness even though it is, in fact, a poison. The epoxide moiety is a carbon electrophile and can be attacked by the nucleophilic DNA bases. Image File history File links Download high-resolution version (1131x1566, 915 KB)By Richard Wheeler (Zephyris) 2007. ... Image File history File links Download high-resolution version (1131x1566, 915 KB)By Richard Wheeler (Zephyris) 2007. ... The cigarette is the most common method of smoking tobacco. ... In chemistry, an electrophile (literally electron-lover) is a reagent attracted to electrons that participates in a chemical reaction by accepting an electron pair in order to bond to a nucleophile. ... In chemistry, a nucleophile (literally nucleus lover) is a reagent which is attracted to centres of positive charge. ...

This molecule intercalates in DNA, covalently bonding to the nucleophilic guanine nucleobases at the N2 position. X-ray crystallographic and nuclear magnetic resonance structure studies show that this binding distorts the DNA,^[5] inducing mutations by perturbing the double-helical DNA structure. This can disrupt the normal process of copying DNA, and may lead to cancer.^[6] This mechanism of action is similar to that of aflatoxin which binds to the N7 position of guanine.^[7] Intercalation induces structural distortions. ... The structure of part of a DNA double helix Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the development and function of living organisms. ... Covalent bonding is a description of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. ... In chemistry, a nucleophile (literally nucleus lover) is a reagent which is attracted to centres of positive charge. ... Guanine is one of the five main nucleobases found in the nucleic acids DNA and RNA; the others being adenine, cytosine, thymine, and uracil. ... Adenine Guanine Thymine Cytosine ... X-ray crystallography or single-crystal X-ray diffraction is an analytical technique which uses the diffraction pattern produced by bombarding a single crystal with X-rays to solve the crystal structure. ... Pacific Northwest National Laboratorys high magnetic field (800 MHz, 18. ... Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ... Chemical structure of aflatoxin B1 Aflatoxins are naturally occurring mycotoxins that are produced by many species of Aspergillus, a fungus, most notably Aspergillus flavus and Aspergillus parasiticus. ...

Benzo[a]pyrene diol epoxide is the carcinogenic product of three enzymatic reactions. Benzo[a]pyrene is first oxidized by cytochrome P4501A1 to form a variety of products, including (+)-benzo[a]pyrene 7,8-oxide.^{[citation needed]} This product is metabolized by epoxide hydrolase, opening up the epoxide ring to yield (-)-benzo[a]pyrene-7,8,dihydrodiol. The ultimate carcinogen is formed after another reaction with cytochrome P4501A1 to yield the benzopyrene diol epoxide. The two carbons of the epoxide are electrophilic, due to an unequal sharing of electrons with the oxygen, facilitating covalent addition to DNA.^{[citation needed]} Cytochrome P450 Oxidase (CYP2E1) Cytochrome P450 oxidase (commonly abbreviated CYP) is a generic term for a large number of related, but distinct, oxidative enzymes (EC 1. ... In general, the epoxide hydrolase system functions in detoxication during drug metabolism. ... An epoxide is a cyclic ether with only three ring atoms. ... The term carcinogen refers to any substance, radionuclide or radiation which is an agent directly involved in the promotion of cancer or in the facilitation of its propagation. ... Cytochrome P450 Oxidase (CYP2E1) Cytochrome P450 oxidase (commonly abbreviated CYP) is a generic term for a large number of related, but distinct, oxidative enzymes (EC 1. ... In chemistry, an electrophile (literally electron-lover) is a reagent attracted to electrons that participates in a chemical reaction by accepting an electron pair in order to bond to a nucleophile. ...

Benzo[a]pyrene induces high concentrations of cytochrome P4501A1 (CYP1A1) by binding to the AHR (aryl hydrocarbon receptor) in the cytosol.^{[citation needed]} Upon binding the transformed receptor translocates to the nucleus where it dimerises with ARNT (aryl hydrocarbon receptor nuclear translocator) and then binds xenobiotic response elements (XREs) in DNA located upstream of certain genes.^{[citation needed]} This process increases transcription of certain genes, notably CYP1A1, followed by increased CYP1A1 protein production.^{[citation needed]} This process is similar to induction of CYP1A1 by certain polychlorinated biphenyls and dioxins.^{[citation needed]} Cytochrome P450 Oxidase (CYP2E1) Cytochrome P450 oxidase (commonly abbreviated CYP) is a generic term for a large number of related, but distinct, oxidative enzymes (EC 1. ... Aryl hydrocarbon receptor or AhR is a basic helix-loop-helix (bHLH) transcription factor that binds to HSP90 in the cytoplasm while inactivated. ... Aryl hydrocarbon receptor or AhR is a basic-helix-loop-helix transcription factor that binds to HSP90 in the cytoplasm while inactivated. ... A xenobiotic response element is a portion of a gene or genes which serves to identify foreign materials, often as the beginning of a cascade which results in the elimination or processing of these materials. ... A micrograph of ongoing gene transcription of ribosomal RNA illustrating the growing primary transcripts. ... It has been suggested that this article or section be merged with Polychlorinated biphenyls (PCBs). ... Space-filling model of 2,3,7,8- tetrachlorodibenzo-p-dioxin Structure of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) Dioxin is the popular name for the family of halogenated organic compounds, the most common consisting of polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzodioxins (PCDDs). ...

Recently, Benzo[a]pyrene has been found to activate a transposon, LINE1, in humans^[8]

References

• Benzopyrene in Barbeque. Newhouse A1. Retrieved on March 5, 2005.
• Lung cancer as consecuence by Benzopyrene in smokers. Lung Cancer. Retrieved on March 5, 2005.
• Levels of Benzopyrene in Burnt toasts. Guardian Unlimited. Retrieved on March 5, 2005.
• DNA interaction with Benzopyrene. DNA. Retrieved on March 5, 2005.
• Crystal and molecular structure of a benzo-a-pyrene 7,8-diol 9,10-epoxide N2-deoxyguanosine adduct: Absolute configuration and conformation. Proceedings of the National Academy of Sciences. Retrieved on January 3, 2006.

1. ^ Benzopyrene and Vitamin A deficiency. Researcher links cigarettes, vitamin A and emphysema. Retrieved on March 5, 2005.
2. ^ Denissenko MF, Pao A, Tang M, Pfeifer GP. Preferential formation of benzo[a]pyrene adducts at lung cancer mutational hotspots in P53. Science. 1996 Oct 18;274(5286):430-2.
3. ^ Data presented by Daniel W. Nebert in research seminars 2007
4. ^ Created from PDB 1JDG
5. ^ Volk DE, Thiviyanathan V, Rice JS, Luxon BA, Shah JH, Yagi H, Sayer JM, Yeh HJ, Jerina DM, Gorenstein DG. Solution structure of a cis-opened (10R)-N6-deoxyadenosine adduct of (9S,10R)-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene in a DNA duplex. Biochemistry. 2003 Feb 18;42(6):1410-20.
6. ^
7. ^ Eaton DL, Gallagher EP. Mechanisms of aflatoxin carcinogenesis. Annu Rev Pharmacol Toxicol. 1994;34:135-72.
8. ^ Vilius Stribinskis and Kenneth S. Ramos (2006). Activation of Human Long Interspersed Nuclear Element 1 Retrotransposition by Benzo(a)pyrene, an Ubiquitous Environmental Carcinogen. Cancer Res 2006; 66: (5).

March 5 is the 64th day of the year in the Gregorian calendar (65th in leap years). ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... Smoke from a wildfire Smoke is a suspension in air (aerosol) of small particles resulting from incomplete combustion of a fuel. ... March 5 is the 64th day of the year in the Gregorian calendar (65th in leap years). ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... March 5 is the 64th day of the year in the Gregorian calendar (65th in leap years). ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... March 5 is the 64th day of the year in the Gregorian calendar (65th in leap years). ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... January 3 is the 3rd day of the year in the Gregorian calendar. ... For the Manfred Mann album, see 2006 (album). ... March 5 is the 64th day of the year in the Gregorian calendar (65th in leap years). ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ...

See also

• cigarette
• Barbecue
• Benzene
• Pyrene, a four-ring analogue

A smoking symbol. ... It has been suggested that Grilling be merged into this article or section. ... Benzene, also known as benzol, is an organic chemical compound with the formula C6H6. ... Flash point non-flammable R/S statement R: 36/37/38-45-53 S: 24/25-26-36 RTECS number UR2450000 Supplementary data page Structure and properties n, εr, etc. ...

External links

• National Pollutant Inventory - Polycyclic Aromatic Hydrocarbon Fact Sheet

• Links to external chemical sources