Biology A level planning experiment of effect of lead ions on amylase

Enzymes combine with reactant molecules (substrate) and bind them closely to one another. The three-dimensional shape of the enzyme molecule must be complementary to the shape of the substrate.

There are many types of enzymes and each has a specific job. Enzymes are particular types of proteins that help to speed up some reactions, such as reactants going to products. One of them is the amylase enzyme. Amylases are found in saliva, and pancreatic secretions of the small intestine. The function of amylase is to break down big molecules of starch into small molecules like glucose; this process is called hydrolysis. Enzymes are very specific; for example, amylase is the only enzyme that will break down starch. It is similar to the theory of the lock

1) Amylase is utilized to break down starch molecules into more simple sugars for use by the body. It performs this function by hydrolyzing glycosidic linkages in the polysaccharide chain.

Specifically, alpha-amylase is produced by the salivary glands of Homo sapiens (Humans) as well as many other mammalian species and is encoded by the gene AMY1A (Tracey 2017, p.22). The enzyme alpha-amylase is able to uptake polysaccharides including starch and glycogen as a substrate then hydrolyze the alpha-1,4-glycosidic linkages that connect the monosaccharides together (Tracey 2017, p.37). This is the reason as to why salivary amylase is also referred to as alpha-amylase (Tracey 2017, p.22).

specific enzyme (Knowles, 1991). One part of the enzyme, salivary amylase, is that alpha amylase is in the saliva of most animals because this enzyme breaks down starch (Jacobsen, Melvaer, Hensten- Pettersen, 1972). In the presence of starch, this enzyme is present in saliva, but is not present when there is no starch present (Jacobsen, Melvaer, Hensten- Pettersen, 1972). The conditions for salivary amylase to have a reaction with starch would change in temperature and enzyme concentration, as well as, monitoring the pH levels (Jacobsen, Melvaer, Hensten- Pettersen, 1972). Salivary amylase is an enzyme is human saliva that helps in digestion of specific substrates, such as starch (Hudman, Friend, Hartman, Ashton, Catron, 1957). It breaks down starch molecules by splitting maltose from the non-reducing end of a gluten molecule (Jacobsen, Melvaer, Hensten-Pettersen, 1972).

In this lab experiment the action of the enzyme Amylase was observed on starch (the substrate). Amylase changed the starch into a simpler form, the sugar maltose, which is soluble in water. Maltose then breaks down the glucose chains of starch in the pancreas and intestines. Amylase is present in human saliva, and begins to act on the starch in the food while still in the mouth. Exposure to heat or extreme PH (acid or base) will denature proteins. Enzymes, including amylase, are proteins; if denatured enzymes can no longer act as a catalyst for the reaction. In the presence of potassium iodide, starch turns a dark purple color; however maltose does not react with I2KI. The rate of fading of starch allows a quantitative measurement of reaction rate.

2. What effect did boiling and freezing have on enzyme activity? Why? How well did the results compare with your prediction?__Boiling caused amylase to be denatured, thus inactivating the enzyme. Freezing has no effect. The function of an enzyme is directly related to its environment, like temperature.__

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.

For the second part of the experiment, one had to use the knowledge learn from viewing protein molecules in FirstGlance in Jmol to analyze the protein PDB ID: 4EEY. The analysis of this protein was done using the RSCB protein data bank (PDB) at (http://www.rcsb.org/pdb/home/home.do).2

Starch, (C6H10O5)n, is a polysaccharide that is made by linking together ∝-glucose molecules and comes in two forms; helix or branched. In humans and other animals, starch is broken down to supply energy to tissues. Pancreatic amylase is an enzyme, secreted by the pancreas into the small intestine, which digests starch into maltose.

The primary protein structure can be likened to a human chain in which each person is assumed to be an amino acid and their hands viewed as the carboxyl and amino groups. The person on one end of the chain, who has a free left hand, is assumed to be the free carboxyl group. The person on the other end, who has a free right hand, is assumed to be the free amino group. Everyone in this chain has a left hand linked to somebody’s right hand and a right hand linked to somebody else’s left hand forming peptide bonds. The heads and legs just like the side chains and hydrogens, do not take part in the linking.

Amylase is a digestive enzyme. The enzyme is found in the salivary glands in your mouth

In this lab our group observed the role of pancreatic amylase in the digestion of starch and the optimum temperature and pH that affects this enzyme. Enzymes are located inside of cells that increase the rate of a chemical reaction (Cooper, 2000). Most enzymes function in a narrow range of pH between 5 through 9 (Won-Park, Zipp, 2000). The temperature for which enzymes can function is limited as well ranging from 0 degrees Celsius (melting point) to 100 degrees Celsius (boiling point)(Won-Park, Zipp, 2000). When the temperature varies in range it can affect the enzyme either by affecting the constant of the reaction rate or by thermal denturization of the particular enzyme (Won-Park, Zipp, 2000). In this lab in particular the enzyme, which was of concern, was pancreatic amylase. This type of amylase comes from and is secreted from the pancreas to digest starch to break it down into a more simple form called maltose. Maltose is a disaccharide composed of two monosaccharides of glucose. The presence of glucose in our experiment can be identified by Benedicts solution, which shows that the reducing of sugars has taken place. If positive the solution will turn into a murky reddish color, where if it is negative it will stay clear in our reaction. We can also test if no reduction of sugars takes place by an iodine test. If starch is present the test will show a dark black color (Ophardt, 2003).

The objective of this lab was to assess the effect that temperature and pH had on pancreatic amylase. Amylase is an enzyme involved in digestion and is secreted by both the pancreas and salivary glands (Pandol, 2010). Both salivary and pancreatic amylase display the same enzymatic activities through their role in the digestion of starch (Pandol, 2010). The goal of both salivary and pancreatic amylase is to hydrolyze starch thus breaking down the polysaccharide into a disaccharide such as maltose (Pandol, 2010). As a result, amylase breaks down these sugars making them more easily absorbed in the body during digestion (Pancreatic Cancer Action Network, 2015). Through this lab we learned about the role of pancreatic amylase and how this enzyme operates under certain conditions.

Numerous enzymes are needed in dough to break down starch into simple sugars that yeast can digest. The process is a very complex one, and includes the enzymes alpha amylase and beta amylase. Starch occurs in two different forms, a branched form called amylopectin and an unbranched chain called amylose.