Examination Of Biliverdin Ix Beta Reductase

Background and Introduction: Enzymes are proteins that process substrates, which is the chemical molecule that enzymes work on to make products. Enzyme purpose is to increase the rate of activity and speed up chemical reaction in a form of biological catalysts. The enzymes specialize in lowering the activation energy to start the process. Enzymes are very specific in their process, each substrate is designed to fit with a specific substrate and the enzyme and substrate link at the active site. The binding of a substrate to the active site of an enzyme is a very specific interaction. Active sites are clefts or grooves on the surface of an enzyme, usually composed of amino acids from different parts of the polypeptide chain that are brought together in the tertiary structure of the folded protein. Substrates initially bind to the active site by noncovalent interactions, including hydrogen bonds, ionic bonds, and hydrophobic interactions. Once a substrate is bound to the active site of an enzyme, multiple mechanisms can accelerate its conversion to the product of the reaction. But sometimes, these enzymes fail or succeed to increase the rate of action because of various factors that limit the action. These factors can be known as temperature, acidity levels (pH), enzyme and/or substrate concentration, etc. In this experiment, it will be tested how much of an effect

B. Catalysis occurs on a specific site on the enzyme (the active site). The active site is usually less than 5% of the surface area of the protein, and is always in a cleft. The rest of the molecule serves to present the active site in a three dimensional structure that is capable of binding substrate and catalyzing the reaction. Binding to a substrate is very specific, and involves ionic interactions, H bonds and van der Waals forces.

After reviewing the basics of enzymes and catalysis, we take a dive into the wonderful

J. Moldovan & B. Nilson, (2010), Lab 4 – Enzyme Kinetics, UBCO BIOL/BIOC 393, UBC Vista accessed Monday, November 8th, 2010.

There may also be sections where the secondary structure is neither helix nor sheet. Then the structure is called a random structure, indicating that it folds in random directions. The amino acids in an alpha helix are arranged in a right-handed helical structure resembling a spring. The alpha helix is the most common form of regular secondary structure in proteins. The beta-sheet is the second form of regular secondary structure in proteins consisting of beta strands connected laterally by three or more hydrogen bonds, forming a generally twisted, pleated sheet. The beta-sheet is sometimes called the beta pleated sheet since sequential neighboring atoms are alternately above and below the plane of the sheet giving a pleated appearance. Turns are the third of the three "classical" secondary structures that serve to reverse the direction of the polypeptide chain. They are located primarily on the protein surface and accordingly contain polar and charged residues. However, they are not very common in discussions of protein structure today.

Discussion The objective of this lab was to observe the enzyme kinetics of Tyrosinase, both under normal conditions and under the influence of two different inhibitors. This required careful measurement and calibration of both lab equipment and reagent solutions. The first step was to obtain the optimized volume (also concentration) of Tyrosinase (partial data shown, calculation shown), determined by monitoring the absorbance of a protein solution (Figure 6 & 11) and using a simple equation to solve for the amount of Tyrosinase that obtained a slope of .1 to .15. The optimized volume added was 33 μL (Figure 11).

Organisms cannot depend solely on spontaneous reactions for the production of materials because they occur slowly and are not responsive to the organism's needs (Martineau, Dean, et al, Laboratory Manual, 43). In order to speed up the reaction process, cells use enzymes as biological catalysts. Enzymes are able to speed up the reaction through lowering activation energy. Additionally, enzymes facilitate reactions without being consumed (manual,43). Each enzyme acts on a specific molecule or set of molecules referred to as the enzyme's substrate and the results of this reaction are called products (manual 43). As a result, enzymes promote a reaction so that substrates are converted into products on a faster pace (manual 43). Most enzymes are proteins whose structure is determined by its sequence of its amino acids. Enzymes are designed to function the best under physiological conditions of PH and temperature. Any change of these variables that change the conformation of the enzyme will destroy or enhance enzyme activity(manual, 43).

The products produced by the first reaction were used as a substrate for the second. In this case the enzyme used NADH, which resulted in the decreased absorbance due to the NADH oxidation to NAD+. In addition, the spectrophotometer was used as a measuring device to follow the change in absorbance of the NADH molecules at 340nm.

The first reaction in the mevalonate pathway begins with the cytosolic enzyme acetoacetyl-CoA thiolase, which condenses two acetyl-CoA molecules to produce acetoacetyl-CoA. In the next step, which is catalyzed by HMG-CoA synthase, acetoacetyl-CoA is condensed with acetyl-CoA to produce HMG-CoA. HMG-CoA reductase, the rate-limiting enzyme of the mevalonate pathway, converts HMG-CoA to mevalonate in a two-step reaction, using two molecules of NADPH (Grunler et al., 1994; Kuzuyama, 2002). Mevalonic acid (mevalonate) is gradually converted into the 5-carbon molecule isopentenyl-pyrophosphate (IPP) via a multi-step phosphorylation and decarboxylation reactions then on to the 15-carbon molecule farnesyl-pyrophosphate (FPP) that is the substrate for

The coenzymes bind to cause the loop on lactate dehydrogenase to move which allows for the substrate to bind between histidine 195 and fourth carbon of the nicotinamide ring

The purpose of this experiment was to test and observe the numerous amounts of factors that influence the activity of the enzyme and that can be done by releasing oxygen gas in a fixed condition and change conditions one at a time.

The class Leu, Trp, Ade dropout plates (Table 2) showed that there are interactions between the Bub1B protein produced between 186 and 613 bp on the Bub1B1 gene and CDC20 protein, as shown in Figure 1. There are interactions between the Bub1B protein produced between 328 and 588 bp and BUB3 protein. There are interactions between the Bub1B protein produced between 588 and 1052 bp and Ppp2r5c protein. There are no interactions between the Bub1B and Zfp207

The objective of the experiment was to find the amount of bixin in plasma when given orally to dogs and to look at the stress and inflammatory biomarkers to measure the immunomodulatory and antioxidant effects of bixin. The authors believed that if bixin is taken orally it will be quickly absorbed by the plasma in dogs and eventually into the leukocytes which should increase immunomodulation. The blood constituent measure in this experiment is leukocytes. The significance of measuring the amount of white blood cells was to find how bixin is absorbed and how much ends up in the leukocytes. Also, the significance is because most of the bixin absorbed is in the mitochondria of leukocytes, which is one of the major organelles in the cell.

Bettelheim, Brown, Campbell and Farrell assert that polypeptide chains do not extend in straight lines but rather they fold in various ways and give rise to a large number of three-dimensional structures (594). This folding or conformation of amino acids in the localized regions of the polypeptide chains defines the secondary structure of proteins. The main force responsible for the secondary structure is the non-covalent

NADH accumulates from glycolysis and thus stop it from reoccurring. In order to get rid