Polycyclic aromatic hydrocarbon-protein

Harford-Cross CF, Carmichael AB, Allan FK et al (2000) Protein engineering of cytochrome P450cam (CYP101) for the oxidation of polycyclic aromatic hydrocarbons. Protein Eng 13 121-128... 

Toxic compounds polychlorinated biphenyls, polycyclic aromatic hydrocarbons, organochlorine pesticides, chlorinated pesticides, dioxins, veterinary drug residues, hormone residues, aflatoxins, toxic compounds in shellfish. Compoimds of nutritional significance in foods vitamins, fat, lipids, carbohydrates, protein, energy-calorific value, proximates, dietary fibre, ash. Other compounds hormones in blood serum... 

Many process mixtures, notably fermentations, require sample preconcentration, microdialysis, microfiltration, or ultrafiltration prior to analysis. A capillary mixer has been used as a sample preparation and enrichment technique in microchromatography of polycyclic aromatic hydrocarbons in water.8 Microdialysis to remove protein has been coupled to reversed phase chromatography to follow the pharmacokinetics of the metabolism of acetaminophen into acetaminophen-4-O-sulfate and acetaminophen-4-O-glucu-ronide.9 On-line ultrafiltration was used in a process monitor for Aspergillus niger fermentation.10... 

Because process mixtures are complex, specialized detectors may substitute for separation efficiency. One specialized detector is the array amperometric detector, which allows selective detection of electrochemically active compounds.23 Electrochemical array detectors are discussed in greater detail in Chapter 5. Many pharmaceutical compounds are chiral, so a detector capable of determining optical purity would be extremely useful in monitoring synthetic reactions. A double-beam circular dichroism detector using a laser as the source was used for the selective detection of chiral cobalt compounds.24 The double-beam, single-source construction reduces the limitations of flicker noise. Chemiluminescence of an ozonized mixture was used as the principle for a sulfur-selective detector used to analyze pesticides, proteins, and blood thiols from rat plasma.25 Chemiluminescence using bis (2,4, 6-trichlorophenyl) oxalate was used for the selective detection of catalytically reduced nitrated polycyclic aromatic hydrocarbons from diesel exhaust.26... 

Covalent binding of chemical carcinogens to cellular macromolecules, DNA, RNA and protein, is wel1-accepted to be the first step in the tumor initiation process ( 1, 2). Most carcinogens, including polycyclic aromatic hydrocarbons (PAH), require metabolic activation to produce the ultimate electrophilic species which react with cellular macromolecules. Understanding the mechanisms of activation and the enzymes which catalyze them is critical to elucidating the tumor initiation process. 

During cooxidation, some substrates are activated to become more toxic than they were originally. In some cases substrate oxidation results in the production of free radicals, which may initiate lipid peroxidation or bind to cellular proteins or DNA. Another activation pathway involves the formation of a peroxyl radical from subsequent metabolism of prostaglandin G2. This reactive molecule can epoxidize many substates including polycyclic aromatic hydrocarbons, generally resulting in increasing toxicity of the respective substrates. 

Reconstituted HRP by modified unmodified protein when polycyclic aromatic hydrocarbons were used as substrates The reconstitution of HRP with the modified [81]... 

Several mechanisms may contribute to the association of meat with colon cancer. The heterocyclic amines and polycyclic aromatic hydrocarbons present in cooked meat are metabolized, in the body, to mutagens that may condense with DNA to form adducts. If the adduct occurs at a vital base, and if the adduct is not promptly repaired, cancer may result. Another possible mechanism is related to the enhanced excretion of bile salts into the intestines that occurs with a high-fat diet. In brief, the increased amount of bile salts (with a high-fat diet) that reaches the large intestines is metabolized by the gut microflora to an increased amount of modified bile salts. Specifically, lithocholic acid and deoxycholic acid are formed. These modified bile salts are thought to contribute to the conversion of a normal gut cell to a cancer cell. Recent studies suggest that chronic exposure of gut cells to these modified bile salts may result in chronic activation of protein kinase C and chronic... 

Boulu, L.G., Crippen, G.M., Barton, H.A., Kwon, H. and Marietta, M.A. (1990). Voronoi Binding Site Model of a Polycyclic Aromatic Hydrocarbon Binding Protein. J.Med.Chem., 33, 771-775. 

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