Elongation synthesis

Chapter 19) Adrenal cortex Liver Fatty acid synthesis Elongation of fatty acids (Chapter 11) Desaturation of fatty acids Detoxification reactions... 

Transcription is catalyzed by DNA-dependent RNA polymerases, which use ribonucleoside 5 -triphosphates to synthesize RNA complementary to the template strand of duplex DNA. Transcription occurs in several phases binding of RNA polymerase to a DNA site called a promoter, initiation of transcript synthesis, elongation, and termination. 

This reaction is reversible when conducted in vitro, but under the conditions of pH and nicotinamide concentration that exist in the cell, it is irreversible. Thus, diphtheria toxin kills cells by irreversibly destroying the ability of EF-2 to participate in the translocation step of protein synthesis elongation. A number of other protein toxins have subsequently been found to ADP-ribosylate and inactivate cellular proteins involved in other essential cellular pathways. For example, cholera and pertussis toxins ADP-ribosylate and inactivate proteins important to cAMP metabolism. 

Elongation factors. Protein factors uniquely required during the elongation phase of protein synthesis. Elongation factor G (EF-G) brings about the movement of the peptidyl-tRNA from the A site to the P site of the ribosome. 

In prokaryotes, each of the reactions of fatty acid synthesis is catalyzed by a separate enzyme. However, in eukaryotes, the enzymes of the fatty acid synthesis elongation cycle are present in a single polypeptide chain, multifunctional enzyme complex, called fatty acid synthase. The fatty acid synthase complex exists as a dimer, with the ACP moiety shuttling the fatty acyl chain between successive catalytic sites, and from one subunit of the dimer to the other. It is, in effect, a highly efficient production line for fatty acid biosynthesis. 

GE2270A 394 is an antibiotic produced by Planobispora rosea ATCC 537731. It inhibits Gram-positive bacteria and anaerobes by acting on the protein synthesis elongation factor (EF) <1991JAN693, 1995T4867>. It contains proline, serine, glycine, two thiazolyl amino acids, and a heterocyclic centerpiece of a trisubstituted pyridine, all in a macrocyclic array. 

Fatty Acids Synthesis, Elongation, and Desaturation. The main objective of feeding fats to animals is to provide a concentrated energy source, not to have the fat stored in the tissues. Recognized EFA requirements are no more than several percent of dry matter at the most, but the critical roles they play in maintaining the metabolic machinery has attracted the majority of current research on dietary fat utilization. 

E. coli membranes contains zinc, which is required for full activity. A functional role for zinc in protein synthesis elongation factor 1 from rat liver has been inferred from the observation that 0.3 mM 1,10-phenanthroline completely abolishes guano-sine 5 -triphosphate binding to EFl there is one zinc per molecule (54 000 Daltons). ... 

Nilsson L and Nygard O (1986). The mechanism of the protein-synthesis elongation cycle in eukaryotes. Effect of ricin on the ribosomal interaction with elongation factors. Eur J Biochem, 161, 111-117. 

See also Fatty Acids, Coenzyme A, Oxidation of Fatty Acids, Fat Synthesis, Elongation of Fatty Acids, Fatty Acid Desaturation, Thiolase... 

Guanosine diphosphate EF-Tu (protein synthesis elongation factor) complex Haemoglobin... 

Protein synthesis initiation by IF-2 Protein synthesis elongation hy EF-Tu and EF-G Polyamine synthesis by ornithine decarboxylase rRNA synthesis by RNA polymerase Acetyl-CoA carboxylase"... 

The five biotin-dependent mammalian carboxylases are acetyl-CoA carboxylase isoforms I and II (also known as a-ACC (EC 6.4.1.2) and /3-ACC (EC 6.4.1.2)), pyruvate carboxylase (EC 6.4.1.1), methyl-crotonyl-CoA carboxylase (EC 6.4.1.4), and propio-nyl-CoA carboxylase (EC 6.4.1.3). ACC catalyzes the incorporation of bicarbonate into acetyl-CoA to form malonyl-CoA (Figure 2). There are two isoforms of ACC. Isoform I is located in the cytosol and produces malonyl-CoA, which is rate limiting in fatty acid synthesis (elongation). Isoform II is located on the outer mitochondrial membrane and controls fatty acid oxidation in mitochondria through the inhibitory effect of malonyl-CoA on fatty acid transport... 

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