How Do You Know That Catalase Is an Enzyme
Enzyme Lab - Ex. 4
| Full general | Overview | Assignment | Analogy |
| Catalase | Amylase | Lipase Bile Salts | Proteases . . Pepsin . . .Trypsin |
| pH | Iodine Test | Benedict's Examination | Phenol Red |
| Quiz | Questions | ||
Enzyme - General Information
In laboratory exercise 4 yous investigate five enzymes: catalase, amylase, lipase, pepsin, and trypsin.Every bit an enzyme works it combines with its substrate and converts it to product(s). Y'all will monitor the activity of the enzymes by observing changes in the amounts of substrate and products.
ENZYME SUBSTRATE - - - - - > PRODUCTSMuch of the laboratory practice is "cookbook", meaning that you follow specific, and at times relatively involved directions. Then, after the passage of a short time, you observe the results (e.1000., a color modify, formation of bubbles). As long as you are careful to follow the directions, the results will exist as expected.The challenge is not then much doing the exercises every bit information technology is agreement what you are doing, why you are doing it in the specific manner specified, and what the results mean.
Iv of the enzymes have special importance in digestion of food past humans.
Although both pepsin and trypsin are proteases, they require quite dissimilar conditions of acidity and alkalinity for their action.
- Amylase from our salivary glands and pancreas digests starch to maltose in our rima oris and small intestine.
- Lipase from the pancreas digests lipids to fatty acids and glycerol in our pocket-size intestine.
- Pepsin is a protease that begins digestion of proteins, breaking them into peptides and amino acids. Pepsinogen, is secreted by gastric glands of the stomach into the stomach. At that place, in the acid environment of the stomach, pepsinogen is converted into pepsin.
- Trypsin is a protease secreted into the small intestine past the pancreas. Equally pepsin, trypsin digests proteins into peptides and amino acids and is made and secreted in an inactive form, trypsinogen.
The 5th enzyme, catalase, is found in cells of most tissues.
We will use homogenized chicken or beef liver as a source of catalase. The other enzymes were obtained commercially from companies that excerpt from fauna tissues.
- Catalase catalyzes the breakdown of hydrogen peroxide, (H2Oii) a toxic past product of metabolic reactions, to the harmless substances, water and oxygen. Nosotros investigate this enzyme because the reaction is extremely rapid and the action of the enzyme tin can exist demonstrated easily by the evolution of oxygen in the class of gas bubbles.
| Enzyme | Substrate | Products | Test |
|---|---|---|---|
| Catalase | H2O2 | HiiO + O2 | Estrus bubbles |
| Enzyme | Substrate | Products | Exam |
| Amylase | Starch | Maltose | I2KI starch Benedicts saccharide |
| Enzyme | Substrate | Products | Exam |
| Lipase | Lipid | Glycerol + Fat Acrid | Phenol Ruddy Acrid |
| Enzyme | Substrate | Products | Test |
| Pepsin | Poly peptide | Peptides + Amino Acids | Disappearance of egg white |
| Trypsin | Poly peptide | Peptides + Amino Acids | Disappearance of egg white |
Full general InformationThe Virtual Enzyme
Enzyme tutorial - animation
Enzyme kinetics -
Enzyme Reaction Tutorials
Free energy, enzymes - problem set
Enzyme kinetics
Enzymes and enzyme activity
Factors affecting enzymes
Issue of pH on enzyme activity
pH tutorial
The part of enzymes in biological reactions -
Factors affecting enzymes -
Enzymes -
Animation - unproblematic
Enzyme blitheness - carboxypeptidase
Animations - links to animations
Animations and links -
| Substrate | Catalase | Products | Test |
|---|---|---|---|
| H2O2 | - - - - - > | HiiO + Otwo | Heat bubbles |
CatalaseHydrogen peroxide (H2O2) is a mutual by-product of metabolic reactions. In high concentration information technology is toxic; therefore, its aggregating in cells would exist harmful. About tissues, however, contain the enzyme catalase, which catalyzes the breakdown of peroxide to water and oxygen as follows:
SUBSTRATE ENZYME PRODUCTS 2 H2O2 Catalase ---> 2 H2O + Otwo + heatThe reaction is extremely rapid. The activeness of the enzyme can be demonstrated easily by the evolution of oxygen in the grade of gas bubbles when an extract of a tissue containing the enzyme is added to a dilute solution of hydrogen peroxide. We will apply homogenized (ground-upwardly) chicken or beef liver as a source of catalase. CatalaseReferences:
- Catalase - general information Classrooms of 21st century
- Catalase - An Boggling Enzyme
- Heat denature enzyme
- Structure of Catalase image and graph
- Links -
| Substrate | Amylase | Products | Test |
|---|---|---|---|
| Starch | - - - - -> | Maltose | I2KI Benedicts |
Amylase
Amylase is an enzyme which catalyzes the hydrolysis of the polysaccharide starch to the disaccharide maltose. Salivary amylase is produced by the salivary glands and pancreatic amylase is produced by the pancreas. If amylase is added to a solution of starch, the starch will be digested to course maltose.SUBSTRATE ENZYME PRODUCTS starch Amylase ----> maltose + maltose + --- etc. ---The rate of the reaction is increased if the enzyme and substrate mixture is brought to trunk temperature (370 C). The progress of the reaction can be visualized by testing the reaction mixture for (1) the disappearance of the substrate (starch) or (2) the appearance of production (maltose). 2 unproblematic tests, iodine test for starch and Benedict's examination for sugar are used for this purpose.
- Amylase References:
- Amylase - Independent study past Amy Caruana (Student at Kean Univ)
- Amylase - results from U. Northward Dakota
- Enzymes amylase, temp, pH, substrate concentration
- Benedicts exam for reducing sugar - image of result
- Amylase How does it work?
- Amylase - starch hydrolysis
- Salivary amylase - pH
| Substrate | Pepsin | Products | Examination |
|---|---|---|---|
| Protein | - - - - -> | Peptides Amino Acids | Disappearance of egg white |
Pepsin is a protease that begins digestion of proteins, breaking them into peptides and amino acids. Pepsinogen, is secreted by gastric glands of the stomach into the tum. There, in the acrid surroundings of the tummy, pepsinogen is converted into pepsin.Although both pepsin and trypsin are proteases, they require quite dissimilar weather condition of acerbity and alkalinity for their action.
- Pepsin References:
- Pepsin -
- Pepsin - molecule of the calendar month
- pH optimum -
- Pepsin - mentions pH optimum
| Substrate | Trypsin | Products | Test |
|---|---|---|---|
| Protein | - - - - -> | Peptides Amino Acids | Disappearance of egg white |
Trypsin is a protease secreted into the small-scale intestine by the pancreas. As pepsin, trypsin digests proteins into peptides and amino acids and is fabricated and secreted in an inactive form, trypsinogen.Although both pepsin and trypsin are proteases, they require quite different conditions of acerbity and alkalinity for their action.
- Trypsin References:
- Trypsin Encyclopedia clarification
- Illustration search for trypsin inside this large file
- Images Google search engine
| Substrate | Lipase | Products | Test |
|---|---|---|---|
| Lipid | - - - -> | Glycerol + Fatty Acid | Phenol Carmine Acid |
Lipase is a fat-digesting enzyme, catalyzing the hydrolysis of fatty to fatty acids and glycerol. The main source of lipase is the pancreas.SUBSTRATE ENZYME PRODUCTS lipid Lipase ---> fatty acrid + fatty acrid + fatty acrid + glycerolIn the following experiment you lot will utilise a solution of commercially available pancreatic lipase to report the hydrolysis of milk fat. To follow the reaction, you will make apply of the fact that fats are neutral, while fatty acids are acidic. The release of fatty acids from fats past hydrolysis will increase the acidity (lower the pH) of the reaction mixture. This change tin be observed by using the indicator dye, phenol red, which is useful for measuring pH values between 6.8 and 8.iv.
- Lipase References:
- Assimilation of Lipids
- Function of Bile
- Digestion and Assimilation gyre downwardly to see diagrams
An Analogy
Suppose y'all are interested in purchasing a Pizza store and wish to investigate how productive the store is without the present owner knowing because, you lot fearfulness the owner will raise the price. And so, instead of going into the store and watching what happens and request to examine the books that record expenses and profits, you lot decide to watch the store from outside.You detect how oftentimes trucks arrive with pizza dough, pizza toppings (cheese, pepporoni, etc.), and other supplies. You likewise observe how often workers leave the store to deliver pizzas to customers.
In this analogy, the pizza supplies are the reactants and the boxed pizzas that are delivered to customers are the end products. The workers within the store that shape the dough, add the toppings and place the pizzas in ovens and finally in boxes are the equivalent of the enzymes.
Although nosotros don't really see the workers doing their task, we tin infer that if the shop is using big quantities of reactants (dough and toppings) and / or making large numbers of end products (pizzas) that the workers (enzymes) must exist very active.
The Assignment
Although y'all will perform the laboratory exercise working as groups of two or three students, brand your report an individual effort.Complete Tables 4.1, 4.two, 4.3 and iv.four. For each table, record your observations at the time that you conduct the experiment. Even so, go out the explanations of the results until the end.
Your explanations should tell why what happened did happen, or tell the value of the information observed. If, for case, in that location was more enzymatic activity in ane tube than in another, what was responsible for the divergence? What does that observation allow us to learn virtually enzymes?
Some of the observations that you lot make are of controls. For these, your explanation might tell what you would non know if the command had not been included. For example, you test solutions labeled maltose and starch with Bridegroom's solution to learn if sugar is nowadays. You are testing sugar and starch to learn if sugar is present. We wait to find a positive reaction with maltose, indicating that sugar is present. Similarly, we expect to discover a negative reaction with starch, indicating that sugar is absent.
Just consider the possibilities.
Thus, the elementary control shows that the bottle labeled maltose did contain carbohydrate and also that the Benedict's reagent did react as expected when maltose was present.
- Perhaps the solution was labeled incorrectly and that only distilled h2o was really in the bottle labeled maltose
- Maybe both solutions were labeled incorrectly and that the canteen labeled maltose independent starch, while the bottle labeled starch contained maltose
- Mayhap the reagent labeled Benedict's solution was made incorrectly and did non work to detect sugar
- Perchance glassware was not cleaned well and was contaminated with sugar.
As indicated in Table 4, be sure to consider as function of your explanation the pH of the environs in which pepsin and trypsin ordinarily piece of work within the human digestive tract.
pH
pH is defined as the negative log10 of the hydrogen ion concentration. Although this definition is intended to help the scientist past allowing one to express very small quantities without the use of cumbersome fractions (e.g. 0.000000001 gm / liter), students oft have difficulty because of two things.
- The more hydrogen ions in that location are, the smaller the pH number.
- A change of each whole number represents a tenfold increase or decrease.
0.00000000000001 gm / l 1 10 10-fourteen gm / fifty 10-fourteen gm / fifty 14 Basic Least H+ 0.0000000000001 gm / 50 one ten 10-13 gm / fifty x-13 gm / l xiii 0.000000000001 gm / l ane x 10-12 gm / l 10-12 gm / l 12 0.00000000001 gm / l 1 x 10-11 gm / 50 10-11 gm / l 11 0.0000000001 gm / l ane 10 10-10 gm / l 10-10 gm / l 10 0.000000001 gm / l ane 10 10-9 gm / l ten-9 gm / l ix 0.00000001 gm / l one x x-8 gm / fifty 10-8 gm / l eight 0.0000001 gm / fifty ane x 10-seven gm / l ten-7 gm / l seven Neutral 0.000001 gm / l one x ten-6 gm / 50 ten-half-dozen gm / l 6 0.00001 gm / l 1 x x-5 gm / l 10-5 gm / l 5 0.0001 gm / l 1 ten 10-4 gm / l 10-4 gm / l four 0.001 gm / l 1 x 10-three gm / l 10-3 gm / 50 iii 0.01 gm / l 1 10 10-2 gm / l ten-2 gm / fifty 2 0.1 gm / l 1 x x-1 gm / 50 10-i gm / fifty one Acidic Most H+ grams [H+] per liter grams per liter grams per liter pH value
- pH Tutorial
- pH optimum
- pH including optimum values for many
- pH - student question and general response
Iodine Test for Starch
The starch examination consists of adding a drop of IiiKI (iodine solution) to the sample to be tested. If the iodine retains its yellow-brown color, starch is absent-minded. If a purple or blue- black color forms, starch is present, and the deeper the color, the greater the amount of starch.test for starch
Benedict's Test for Reducing Saccharide
The sugar test is performed by adding a small amount of Benedict'southward Reagent to the sample and bringing the mixture to a eddy. If the Benedict'south Reagent retains its clear blue colour and no precipitate is formed, carbohydrate is absent. The presence of sugar is indicated by the development of a precipitate which may range in color (indicating increasing amounts of sugar) from green, through xanthous and orangish, to red. This examination depends upon the ability of certain sugars to reduce the cupric (Cu++) copper present in the Benedict's Reagent to the cuprous (Cu+) course.
- Bridegroom's test
- Benedicts test for reducing sugar
0 *Blueish None + Green Some ++ Yellow More +++ Orange Much . . . . . . . ++++ Crimson Virtually Color Symbol Description Amount of Amylase Action * blueish = 0 (no precipitate; no colour alter)
Phenol Cherry-red Indicator Dye
The indicator dye, phenol ruby, is useful for measuring pH values between 6.8 and 8.4. You will employ phenol cherry to notice changes in pH that result from the acidity of the fatty acids that are formed equally the triglycerides in foam are digested forming fat acids and glycerol. Yous will add NaOH (sodium hydroxide) to all tubes at the start making all tubes initially alkaline. The more than enzyme activity, the more fatty acids, the more acid (lower pH), the more "yellow" the tube volition go.
+++ Fuschia Element of group i None . . . . . . . ++++ Red Neutral Some ++ Yellow Acrid Well-nigh Color Symbol Description pH Amount of Lipase Activity
pH Colour (of Indicator) acrid yellow neutral red (this may be a peach color) alkali metal pink (this may be fuchsia or "hot" pink)
Bile Salts
Fat digestion is facilitated by the presence of bile salts (a component of bile produced in the liver), which bring near a concrete (not enzymatic) breakdown of big fat aerosol into smaller particles. This process is called emulsification.
QUESTIONS
- What simple experiment might you perform to test the hypothesis that an enzyme is not used up during the reaction?
- What simple experiment might you perform to test the hypothesis that an enzyme combines with its substrate when it acts?
- Meat tenderizer is an enzyme, and and so are some laundry products (enzyme detergents used as presoaks). Practice any of the properties you investigated today apply to these enzymes? Tin you call back of any other household or commercial uses for enzymes?
- What kinds of chemicals might you lot add to attempt to speed the activity of an enzyme or to inhibit its action?
- If proteases such every bit pepsin and trypsin digest protein, why don't they digest the stomach and small intestine, which are made from protein?
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Source: http://samson.kean.edu/~breid/enzyme/enzyme.html
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