This enzyme acts as an escort for ubiquitin to its next destination E3 ligase enzyme. E2 ubiquitin conjugating enzyme Figure 16: Schematic representation of transfer of activated Ubiquitin from E1 activating enzyme to E2 conjugating enzyme The E3 enzyme act as a platform on which the target protein substrate and the active E2 ubiquitin complex can meet and interact. The E3 enzyme is extremely fussy about exactly which E2 enzyme and which protein can interact. The correct E2 enzymes loaded with activated ubiquitin could move in position itself correctly on the E3 ready for action. Skp 1 Target Protein Figure 17: Schematic representation of Target protein and ubiquitin conjugation in skp 1 Note: The Target Protein attached to the Skp 1 through F Box (Atrogin-1) which was not depicted in the figure.
Enzymes. Lipids (Lipase) Lipase are secreted by the small intestine and pancreas. They digest complex lipids (fats) molecules into simpler, more soluble fatty acid and glycerol molecules. They exist of fats and oils and are made up of the elements carbon, hydrogen and oxygen and the most common type known of is the triglyceride. A triglyceride is made up of 3 fatty acid chains joined to a glycerol molecule.
INTRODUCTION: Arginase is an enzyme- enzymes are biological catalyst which drives a reaction at the speed of life. Arginase is a hydrolase, hydrolases catalyze hydrolysis reactions, this is determined via the E.C number (Nelson and Cox 2008). Arginase has the EC number is 184.108.40.206 (Schomburg 2015). The enzyme ‘commission number’ is the arithmetical classification that is used for enzymes which indicates the chemical reaction they catalyze. EC 3 are hydrolases, which forms two products from the substrate via hydrolysis.
The oxidative decarboxylation of Pyruvate is carried out by the pyruvate dehydrogenase complex. This multi-protein complex is composed of three enzymes; 1) pyruvate dehydrogenase, 2) dihdrolipoyl transacetylase, and 3) dihyrolipoyl dehydrogenase. The intermediate products formed by this complex are not released and remain bound to the enzyme. The breakdown of fatty acids by the β-oxidation pathway is carried out by four separate enzymes found in the mitochondrial matrix; 1) fatty acyl-CoA dehydrogenase, 2) enoyl hydratase, 3) β-hydroxyacyl-CoA dehydrogenase 4) β-ketoacyl-CoA thiolase. Each cycle of the pathway shortens the fatty acyl-CoA chain by two carbon units.
It is a more often observed biotransformation pathway for small endogenous compounds, but also plays a role in the metabolism of macromolecules like nucleic acids. Compounds can undergo N-, O-, S- and arsenic methylation catalyzed by enzymes called methyltransferases, employing S-adenosylmethionine as the methyl donor.95,98 Amino acid conjugation reactions are a route of metabolism of xenobiotic carboxylic acids. The enzymes of conjugation reside in mitochondria. Mechanistically, it differs from the other conjugation reactions. It involves initial activation of the carboxylic acid moiety with ATP, generating an acyl adenylate and pyrophosphate.
The first one has REC8 in the protein complex, while the second and third groups have Rad21L and Rad21Scc1 resectively (Uhlmann, 2011). The Rad21L containing group is thought to act as a foundation for lateral-element formation because only Rad21L recruits SYCP1. When the recombination is complete, Rad21L gets dissociated from the complex as a result of phosphorylation. This dissociation can result in synaptonemal-complex disassembly. Thereafter, the meiotic cohesin complexes containing Rad21Scc1 is bound to the chromosomes (Figure 1.8) (Uhlmann,
• Enzyme Kinetics Enzyme kinetics Introduction It is the study of those reactions that are moderated by enzymes. In enzyme kinetics, the rate of reaction is measured and the effects of different conditions of the reaction are found out. Enzymes are protein in nature that moderate other molecules — the enzymes ' molecules . These target molecules bind to an enzyme 's activity site and are transformed into completed products through a series of steps known as enzymatic mechanism. These mechanisms can be divided into single-step and multiple-step mechanisms.
The mechanism of attenuation in trp operon The process of controlling transcription termination by the rate of translation of the attenuator is termed as attenuation. In bacterial cells transcription and translation are coupled. The leader sequence (trpL) controls the operon through attenuation. The leader sequence has 4 main regions with some kind of palindromic sequence. When the amount of tryptophan is low the translation of domain1 (requires trp) slows down.The domains 2& 3 pairs which allows the continued transcription, resulting in the biosynthesis of tryptophan.
Tryptic digestion of the final phosphoprotein residue and detection of the increased phosphorylation in the ninhydrin-staining band of peptides derived from synaptosomes of trained mice is further evidence of this. Additional proof of incorporation of radioactive phosphate into proteins was obtained by hydrolysing the phosphoprotein residue with pronase or HCl, followed by separation of the phosphoserine, phosphothreonine, and inorganic phosphate (Table 4). HCl digestion appeared to be a more effective method of hydrolysis, since more radioactivity was recovered and less extraneous ninhydrin-staining material was obtained during electrophoretic separation. The combination of Dowex column chromatography with electrophorectic separation was the best way to separate phosphoserine, phosphothreonine, and orthophosphate from
Globin- It is a protein surrounding & protecting the heme molecule. Heme synthesis: Heme synthesis is carried out in mitochondria & cytosol of the cell involving cascade of steps :- 1) The first step occurs in mitochondria, where condensation of succinyl-CoA & glycine is carried out by enzyme ALA-synthase resulting in product formation i.e. 5-aminolevulinic acid. 2) 5-aminolevulinic acid is transported to the cytosol for formation of porphobilinogen molecule. 3) After formation