ABSTRACT
Enzymes are highly specific and can distinguish isomers of the same molecule. The enzyme invertase specifically catalyzes the reaction of the conversion of sucrose to its individual carbohydrates glucose and fructose. It does not catalyse the reaction of maltose to 2 glucose or lactose to galactose. In this experiment, titrimetric and spectrophotometric methods were used to determine the specificity of invertase by determining the amount of glucose converted from the given disaccharides. The results show that sucrose yielded the least amount of glucose and got the lowest absorbance reading.
INTRODUCTION
Enzymes are globular proteins. Their folded conformation creates an area known as the active site. The nature and arrangement
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Overall, kinetic assays of enzymes are performed to determine substrate specificity, enzyme performance (turnover), characteristics of the mechanism of action, and finally, fundamental kinetic constants describing the mechanism.
The initial reaction rates of enzymes are known to be affected by a variety of factors including: enzyme concentration, substrate identity, substrate concentration, pH, temperature, and the presence, or absence, of known inhibitors.
Invertase which is also known as beta-fructofuranoside fructohydrolase (EC 3.2.1.26) is a catalyst for sucrose hydrolysis yielding invert sugar. Its name refers to its ability to change the direction of optical rotation of sucrose solution as a result of hydrolysis to glucose and fructose. Although invertase is primarily known for the inversion of sucrose, it can be used to digest other disaccharides, trisaccharides, and fructans to make syrups of invert sugars, meliobiose from raffinose, gentiobiose from genanone, and fructose from inulin. The hydrolysis of sucrose by invertase was used as a model by Michaelis and Menten (1913) and served as a basis for most of theories of enzyme kinetics using sucrose and invertase. Invert sugar has been used to a great extent in the food industry such as in beverage and confectionery products. Invert sugar can be produced by a chemical process or biochemical process: using invertase as a catalyst. Nowadays, the
Used to see if the temperature of the water is at 37oc – 40oc and if
Enzyme catalysis is dependant upon factors such as concentration of enzyme and substrate, temperature and pH. These factors determine the rate of reaction, and an increase in temperature or pH above the optimum will
The aim of the study is two-fold: to study the rate of absorbance with increasing concentration of glucose, and to measure the activity of enzyme yeast invertase on sucrose. In task 1, the product formation was measured using 3, 5-dinitrosalicyclic acid that reacts with glucose leading to a change in colour from yellow to reddish brown. In task 2, the enzyme kinetics of yeast invertase on sucrose was studied. The absorbance values of the corresponding volumes of the solutions were measured using a spectrophotometer. Michaelis-Menten curve and Lineweaver-Burk Plot were made in order to estimate the values of Vmax and Km
Enzymes are types of proteins that work as a substance to help speed up a chemical reaction (Madar & Windelspecht, 104). There are three factors that help enzyme activity increase in speed. The three factors that speed up the activity of enzymes are concentration, an increase in temperature, and a preferred pH environment. Whether or not the reaction continues to move forward is not up to the enzyme, instead the reaction is dependent on a reaction’s free energy. These enzymatic reactions have reactants referred to as substrates. Enzymes do much more than create substrates; enzymes actually work with the substrate in a reaction (Madar &Windelspecht, 106). For reactions in a cell it is
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
gluconeogenesis 21. sucrose Part II: Putting It All Together Multiple Choice 1. A 2.
List three conditions that would alter the activity of an enzyme. Be specific with your explanation.
The independent variable in this investigation is pH. Each individual enzyme has it’s own pH characteristic. This is because the hydrogen and ionic bonds between –NH2 and –COOH groups of the polypeptides that make up the enzyme, fix the exact arrangement of the active site of an enzyme. It is crucial to be aware of how even small changes in the
Substrate concentration also affects the rate of reaction as the greater the substrate concentration the faster the rate of reaction and all the active sites are filled. At this point the rate of reaction can only be increased if you add more enzymes in to make more active sites available.
The sucrose concentration in the solution was varied to 10%, 20%, 30%, 40% and 50% in order to examine the effect of varying sucrose concentration on the CO2 production of yeast cells.
“Enzymes are proteins that have catalytic functions” [1], “that speed up or slow down reactions”[2], “indispensable to maintenance and activity of life”[1]. They are each very specific, and will only work when a particular substrate fits in their active site. An active site is “a region on the surface of an enzyme where the substrate binds, and where the reaction occurs”[2].
Enzymes are central to every biochemical process. Due to their high specificity they are capable of catalyzing hundreds of reactions that signifies their vast practical importance.
reaction rate increases. If the temperature of an enzyme gets to high the reaction rate will slow
Enzymes are natural catalysts that work from the ability to increase the rate of reaction by decreasing the activation energy of a reaction. (Blanco, Blanco 2017) An enzyme can do this 10^8- to 10^10 fold, sometimes even 10^15 fold. (Malacinsk, Freifelder 1998) The substrate will momentarily bind with the enzyme making the enzyme-substrate complex, of which the shape of the substrate is complimentary to the shape of the active site on the enzyme it is binding with. There are two main theories as to how an enzymes and substrates interact, the lock-and-key model and induced fit theory. The lock-and-key model suggests that the enzyme has a specific shape that fits the substrate and only that substrate. The induced fit theory says the active site and substrate are able to change shape or distort for the reaction to take place with (Cooper,
To study the effects of temperature, pH, enzyme concentration, and substrate concentration there were certain steps that were followed in order to conduct this experiment. Each factor had a separate procedure to follow to find how each had a different effect on the enzyme.