Explore BrainMass

Explore BrainMass

    Enzyme, Catalysts and Reactions

    Enzymes, or biological catalysts, are three-dimensional globular proteins. Enzymes are integral in biological systems, they function to speed up metabolic reactions by lowering the activation energy of the reaction. Activation energy is the minimum amount of energy that is required to initiate atoms or molecules to a condition in which they can undergo chemical transformation of physical transport1. Examples of enzymes are amylases, proteases, and lipases found in the human digestive system.

    Due to the complex folding in proteins, enzymes have substrate specificity. Binding of substrates occur at the active site, and this process can be shown through the ‘Lock and Key’ model or the ‘Induced Fit’ model. Enzymes can use cofactors, helper molecules, in catalyzing reactions. Cofactors can be classified as tightly bound or loosely bound to the enzyme, and organic or inorganic.  

    Factors that affect enzyme activity are enzyme concentration, substrate concentration, temperature, pH and inhibitors. Derivation from optimal temperature and pH conditions denature the enzyme – the quaternary, tertiary and secondary structure of the protein is modified. Denaturation causes the enzyme’s active site to lose substrate specificity, and overall enzyme function.  Inhibitors act to decrease enzyme activity by binding and effectively blocking the active site, and there are four main types: competitive, uncompetitive, non-competitive and mixed.

    Enzyme catalysis can be defined by their Vmax and Km which are both important in the Michaelis-Menten formula of enzyme kinetics. Vmax is the maximal velocity of enzyme catalysis, or how fast the enzyme can degrade the substrate. Km is substrate concentration where half of the enzyme’s active site are occupied (½ Vmax), this is called the Michaelis Constant. 

     

    References

    1 Activation Energy. (n.d.). In Encyclopedia Britannica online. Retrieved from http://www.britannica.com/EBchecked/topic/4535/activation-energy

    © BrainMass Inc. brainmass.com March 29, 2024, 3:29 am ad1c9bdddf

    BrainMass Solutions Available for Instant Download

    Properties of Enzymes and Catalysis

    Which of the following statements is true of enzyme catalysts? (a) They are generally equally active on D and L isomers of a given substrate (b) They can increase the reaction rate for a given reaction by a thousand-fold or more (c) They can increase the equilibrium constant for a given reaction by a thousand-fold or more.

    Hypothetical experimental scenario or data

    For this assignment, use your understanding of enzymes along with your scientific reasoning skills. This assignment provides you the opportunity to demonstrate your grasp of this module's concepts along with your capacity to interpret scientific data and draw conclusions from it. A biologist is studying the behavior of a newl

    Photosynthesis, Glycolysis Fermentation and Enzyme Catalysts

    Whether it was volcanic activity that spewed sulfur dioxide and ash into the atmosphere, or a giant meteor that crashed into the Earth blasting dust and debris into the sky, both theories of what caused the dinosaurs to become extinct share one critical similarity -- light from the sun was obliterated. The result of the months'

    Calculations for Determining a Titer

    The purpose of the experiment that took place was to determine the titer of B-D-galactosidase using the enzyme-linked immunosorbent assay. I used a formula obtained from class mates to find the titer. I want to be sure this is the correct method for determining the titer. I attached my data, including the results from the plate

    Anabolic steroids, Synthetic steroids, and HGH: Use & Abuse

    1. Define the terms anabolic steroid, synthetic steroid and human growth hormone. Explain how they are similar and how they are different. 2. Discuss the potential risks and dangers associated with using steroids and human growth hormone.

    Rate of Reaction of a Kinase

    An investigation was set up to observe the effect of varying concentrations of the substrate galactose(S) on the rate of reaction of the kinase,v, with and without an added artificial nucleoside monophosphate (UMP)similar to AMP. Data is given below: rate of reaction v/nmol min^-1 Galacto

    Lab Report on Enzyme Kinetics

    Sample Laboratory Report for a 400 level biochemistry lab for Majors. Topic: Enzyme Kinetics Include thorough introduction, Methods, Data, Results & Discussion sections. No graphs are provided!

    Biochemistry Multiple Choice: Enzymes

    9. Which of the following is true? a. Enzymes force reactions to proceed in only one direction b. Enzymes alter the equilibrium of the reaction c. Enzymes alter the standard free energy of the reaction. d. All of the above. e. None of the above 10. Which of the following is NOT a way in which enzymes stabilize a transi

    Problems About Enzymes

    Would you help me with the following questions? An enzyme is found that catalyzes the reaction Aï??B. Researchers find that the Km for the substrate A is 4 uM, and the kcat is 20 min-1. a. In an experiment, [A]=6 mM, and the initial velocity, V0, was 480 nM min -1. What was the [Et] used in the experiment? b. In anot

    Enzymes and Reaction Catalysis

    Would you help me with the following question? An enzyme catalyzes a reaction at a velocity of 20 umol/min when the concentration of substrate (S) is 0.01 M. The Km for this substrate is 1 x 10-5 M. Assuming that Michaelis-Menten kinetics are followed, what will be the reaction velocity when the concentration of S is a) 1 x

    Enzymes for Michaelis-Menten Equation

    Would you help me with the following questions? Give the Michaelis-Menten equation and define each term in it. Does this equation apply to all enzymes? If not, to which kind does it not apply? In deriving the Michaelis-Menten equation, an assumption called the steady state assumption is made. What does this assumption

    Cellular Respiration, Photosynthesis and Enzyme Function

    Cellular Respiration and Photosynthesis co-exist as paired metabolic processes. Photosynthesis uses light energy to convert carbon dioxide into glucose, a simple sugar, in two steps, the light dependent and light independent reactions. Oxygen is produced as a by product during photosynthesis. This reaction stores energy in th

    Enzymes, Inhibition and Allosteric Control

    An enzyme and its substrate are combined in a test tube but no product is formed. Another molecule is added to the tube, and now the product is formed at the normal rate. Give 2 reasons. This has to do with inhibition, but how do I know what kind of inhibition is working on the substrate? If an allosteric control was added

    reaction catalyzed by lactase

    Lactase hydrolyzes lactose into glucose and galactose. galactose is then converted to another glucose by galactosidase. How would I state the reactions involving these enzymes using word equations? i need word equations with descriptions for example. for example. combustion of propane to produce carbon dioxide and water

    Citric Acid Cycle Enzymes

    For each of the eight citric acid cycle enzymes, do the following: a. Write the name of the enzyme. b. Write a balanced equation for the reaction catalyzed. c. Name the cofactor(s) required by each enzyme reaction. d. Determine which of the following describes the type of the reaction(s) catalyzed: condensation (carb

    You characterize a new enzyme's kinetics.

    You characterize a new enzyme's kinetics. Using a saturating (very high so all E is ES) substrate concentration, you measure the initial rate of the reaction at various enzyme concentrations. Does this data fit the Michaelis Menton model/equation? If not, what may be happening? E (nM), rate (mM,s) 5, 50 10, 225 15

    Enzyme Kinetics and the Michaelis-Menten Equation

    1. A new enzyme you are studying has a Km of 7.0mM and a kcat of 126 per second. What will be the initial rate of reaction in units mM/min when 9.3 nanometer enzyme is reacted with 2.7 mM substrate. Report your answer in units if mM/min to nearest 1mM/min? 2. A new enzyme you are studying has a Km of 12.6 mM and a kcat of

    Question about Enzyme properties.

    Which of these statements regarding enzymes is FALSE? A) Enzymes are proteins that function as biological catalysts B) Enzymes display specificity for certain molecules to which they attach C) The activity of enzymes can be regulated by factors in their environment D) Enzymes provide energy for the reactions they cat

    Determining Activation Energy from Rate Constant

    Here is the problem I have to solve: If 10 g of pure carbonic anhydrase catalyzes the hydration of 0.30 g of carbon dioxide in 1 min at 37 degrees C under optimal conditions, what is the turnover number (kcat) of carbonic anhydrase (in units of min-1)? I have already calculated the turnover number, which is 2.0 x 107 min-1,

    Enzymes inhibitors

    Compare competitive and noncompetitive in terms of A) how Km is effected in presence of inhibitor, B) how Vmax is effected in presence of inhibitor, C) where inhibitor would bind to the enzyme

    Enzyme Kinetics & Steady State

    For a MM reaction k1=5x10^7 k-1=2X10^4 k2=4x10^2 i calculated Km and Ks to be equal at about 4 x10^-4M Does substrate binding achieve equilibrium or the steady state? Could you clarify when you have ph=pkA how you get whether it is -1/2 or +1/2 or in the other case +1/3 or -1/3. How do you tell whether it is + o

    Enzymes and Kinetics

    I need help on how to approach this problem: What is the Km of an enzyme if, at [S] = 10^-3 M, 25% of the maximum velocity of the reaction is obtained? What is the ratio of substrate concentrations of a reaction proceeding at 90% and 10% of Vmax, respectively? ------- I know the basis of enzyme kinetics. I just don't

    Enzyme

    (See attached file for full problem description with proper symbols and equations) 2. Carbonic anhydrase of erythrocytes (Mr 30,000) is among the most active of know enzymes. It catalyzes the reversible hydration of CO2: H2O + CO2 H2CO3 which is important in the transport of CO2 from the tissues to the lungs. If 10&#

    Enzyme basic units

    This is a question on enzymes - can't seem to come up with an answer. What are the basic units of enzymes and how are these units arranged and under what conditions do enzymes work best?