· RNA polymerase II synthesizes precursors of mRNAs and most snRNA and microRNAs. This is the most studied type, and due to the high level of control required over transcription a range of transcription factors are required for its binding to promoters. · RNA polymerase III synthesizes tRNAs, rRNA 5S and other small RNAs found in the nucleus and cytosol. There are other RNA polymerase types in mitochondria and chloroplasts. In bacteria, the same enzyme catalyzes the synthesis of mRNA and ncRNA. RNAP is a relatively large molecule. The core enzyme has 5 subunits (~400 kDa): · 2: the two subunits assemble the enzyme and recognize regulatory factors. Each subunit has two domains: CTD (C-Terminal domain) binds the UP element of the extended promoter, and NTD (N-terminal domain) binds the rest of the polymerase. · : this has the polymerase activity (catalyzes the synthesis of RNA) which
procedure Ibuprofen in body It acts on compounds called prostaglandins: Physiologically active lipid compounds having diverse hormone Found in almost every tissue in human They are derived enzymatically from fatty acids They bring out inflammatory response Ibuprofen's action as a painkiller and fever-reducing compound is due to its ability to inhibit the synthesis of prostaglandins It does this by interfering with the action of an enzyme called cyclooxygenase which catalyzes the conversion of a compound called arachidonic acid into prostaglandins 4 step Ibuprofen synthesis First step: Nucleophilic addition Reduction of the carbonyl group C=O by sodium tetrahydridoborate produces a secondary alcohol group CHOH. Second step: Sn1 nucleophilic substitution of the hydroxyl group To improve reactivity of alcohols the leaving anion OH is converted into H2O CH3)3COH + HCl (37%) (CH3)3COH2(+) Cl()
added phosphates (Ruusunen and Puolanne healthier. 2005). The use of some nonmeat components can Another way to reduce the required be submitted to food regulation (e.g., addi- amount of salt and phosphate is to use micro- tives defined in the Council Directive 89/107/ bial transglutaminase (MTG). It is a calcium- EEC 1989). Most food additives are consid- independent enzyme that catalyzes the ered safe. However, some are known to be polymerization and crosslinking of proteins carcinogenic or toxic. Allergic reactions to through the formation of covalent bonds colorings and hyperactivity from phosphates between protein molecules (Carballo et al. have been reported for sensitive individuals. 2006; Heinz 2007). Although the addition Moreover, some nonmeat ingredients, such
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