Enzyme Lab Report

• The lack of functional aldolase B results in accumulation of fructose-1-phosphate in liver cells.

As seen in Figure 1, the EMP pathway begins with glucose, a six carbon monosaccharide. In the first reaction, a phosphate group is transferred from ATP via substrate-level phosphorylation via hexokinase to yield glucose-6-phosphate. In the second reaction, it undergoes an isomerization to yield fructose-6-phophate. In the third reaction, another phosphate group is transferred from ATP to yield fructose-1, 2-bisphosphate and is catalyzed by the important regulatory enzyme phosphofructokinase. At this point in the pathway, the molecule still contains six carbons. However, in the fourth reaction, the six carbon molecule is broken into two three carbon molecules: glyceraldehyde-3-phosphate and dihydroxyacetone-3-phosphate catalyzed by aldolase.

One of the most significant reactions in Glycolysis is reaction one which involves the phosphorylation of glucose to form glucose-6-phosphate. Through the transfer of the hydrolysis of ATP, this supplies energy for the reaction and makes it essentially irreversible, having a negative free energy change, which allows for a spontaneous reaction in cells. Although the preparatory phase is energy consuming and uses up 2 ATP, the pay off phase synthesizes 4 molecules of ATP, with the transfer of 4e- via 2 hydride ions to 2 molecules of NAD+. Therefore, a net gain of 2 ATP is achieved through the glycolytic pathway alone. Following the glycolytic pathway, due to the absence of oxygen, as oxygen cannot be supplied fast enough to undergo aerobic respiration, the athlete will instead, undergo lactic acid fermentation. Lactic acid fermentation involves pyruvate that is formed from the glycolytic pathway to be reduced to lactate, with the aid of the enzyme, lactate dehydrogenase, while the coenzyme Nicotinamide Adenine Dinucleotide (NADH) is oxidised to NAD+. The product NAD+ then re-enters the glycolytic pathway in order to produce 2 ATP. This process of lactic acid fermentation produces 2 ATP for each cycle, and thus, rapidly supplies the body with a small amount of energy. However, with the buildup of lactic acid in the body, the athlete will eventually encounter the feeling of discomfort as this accumulation of lactate causes the body to

Glucagon acts on liver cells to promote breakdown of glycogen into glucose and formation of glucose from lactic acid and certain amino acids.

bonds and taking a glucose molecule off of the structure (Ball, Vialle, Alonso-Casajus, Duavillee, Munoz, Baroja-Fernandez, Moran-Zorzano, Eydallin, Pozueta-Romero, 2006). The conditions for the reaction of Phosphorylase and

This conversion allows for glycolysis to continue in the first stage of glycolysis. In this step, an ATP is broken down into ADP and phosphate to supply the energy for this change (exergonic reaction). On the other hand, when citrate or ATP levels are high, it binds to PFK-1 and inhibits it, which hinders the conversion of Fructose 6-phsophate to Fructose 1,6-biphosphate. This in turn slows down the progression of steps in glycolysis due to the lack of Fructose 1,6-biphosphate being present.

4. Fructose is component of sucrose, normal table sugar, along with glucose. Whereas glucose is able to immediately enter into glycolysis, fructose is not. Fructose is broken down via fructokinase into fructose- 1-phosphate. Fructose – 1-phospate then gets converted into DHAP+ glyceraldehyde via aldolase B. DHAP+ glyceraldehyde is used in glycolysis to produce pyruvate that goes into the citric acid cycle to produce ATP

Aldolase is an enzyme that consists of four polypeptide chains that are identical. The enzyme itself is commonly found in a rabbit muscle tissue where it is recruited to catalyse the breakdown of the fructose1,6-biphosphate to two products; dihydroxyacetone and glyceraldehyde

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).

Tanner MathenyBIO-182L2 February 2017Dr. FrancisIntroduction An enzyme is a catalyzes chemical reactions with in a cell. Enzyme are specific on a certain kind of substrate this is based on the structure of the active site if the enzyme, the site where the substrate reaction occurs, and the structure of the substrate. The active site binds with the substrate and creates an environment that is optimal for the substrate chemical reaction to occur.

Invertase, also known as beta-fructofuranosidase is a digestive enzyme that catalyses the hydrolysis (breakdown) of sucrose (table sugar) to glucose.. It is used in combination with other carbohydrates to enhance overall starch and sugar digestion. Invertase can hydrolyse the connection between glucose and fructose; this means that it uses water break sucrose into to separate monomers. This leaders the enzyme to be inhibited by ‘increased concentrations of sucrose of invertase.’

In step 4 fructose 1,6-biphosphate is cleaved by aldolase to form dihydroxyacetone phosphate and glyceraldehyde 3-phosphate in an endergonic reaction (ΔG’˚=23.8KJ/mol). In step 5 dihydroxyacetone phosphate is converted to glyceraldehyde 3-phosphate by triose

Fructose-1, 6-bisphosphate is a key regulatory step in gluconeogenesis, as well as many other intracellular metabolic pathways . During, gluconeogenesis there is an important process in which there is a conversion of glucose to pyruvate which is known as glycolysis. This process will require three irreversible steps that have a very high negative free energy that is in the forward reaction. So, in order to have a conversion from pyruvate into glucose, the pathway will require the use of enzymes, which will allow the bypassing of these irreversible steps. One of the enzymes that is used in this process is called Fructose 1, 6-bisphosphatase (Kelley, 2006). This step is a very important step in gluconeogenesis, being that it needs to have fructose bisphosphatase to catalyze the conversion of fructose-1, 6-bisphosphate into fructose 6-phospahate, and inorganic phosphate, that without it can block the pathway. Its activity is high regulated by the levels of Adenosine Monophosphate, fructose 2, 6-bisphosphate and also citrate (Kelley, 2006). When deficiencies are present in this pathway and devoid of this conversion, glycerol into glucose, it will lead to fasting hypoglycemia, lactic acidosis and other physiological conditions. This enzyme is highly active within the liver and the intestines. Therefore, when the liver glycogen stores are no longer available, the physical properties of the body will fight for its homeostasis (Eren, 2013) by converting a three

ATP, one of multiple high energy compounds that enable the cell to fuel its processes

Hereditary Fructose Intolerance (HFI) is a recessive disorder pertaining to those who lack the functional enzyme Aldolase B. It affects the kidneys, small intestine and the liver (Wong, 2005). Our bodies require the glycolytic enzyme Aldolase B to metabolize fructose-1-phosphate in the liver during digestion, and without this enzyme it is not possible to do. The consequences of eating honey, fruit and some vegetables that contain fructose result in the accumulation of fructose-1-phosphate, which then inhibits glycogen phosphorylase (Coffee, 2002). In patients who are diagnosed with HFI, the enzyme glycogen phosphorylase gets broken down into glucose-6-phosphate which is required to metabolize glycogen into glucose-6 phosphate. Therefore glucose cannot be released into the blood from the liver. The outcome results in the blood glucose levels drop leading to hypoglycemia.