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The investigators studying the protein changes during aging examined the enzyme activity in the cells extracted from the Caenorhabditis elegans, a nematode worm. The cell extracts were then treated to conserve the enzymatic activity. Although, the investigators noted that some of the proteins were broken down by the process of extraction. The centrifugation of the extracts was performed and seven fractions were collected for isolating the location of the protease enzyme activity, the enzyme called cathepsins. The fraction and the eukaryotic cellular structure in which the enzymatic activity is most active.
Introduction:
The Caenorhabditis elegans is a transparent nematode, which is free-living and it is approximately 1mm (millimeter) in length. It resides mostly in the temperate soil environments. It is the unsegmented pseudocoelomate and also does not have respiratory systems. The males have a special tail and spicules are present on the tail for mating purpose.
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Chapter 4 Solutions
Biology: The Dynamic Science (MindTap Course List)
- Discuss how the equation for enzymatic reaction (given below) was demonstrated in the experimental results in Table 1. Use the appropriate color codes (-), (+), (++), (+++) to describe the expected results in Table 1 Table 1. Enzyme Action MIXTURE ENZYME ACTIVITY Water + catechol (tt A) Enzyme + catechol (tt B) Water + enzyme (tt C)arrow_forwardPenicillin is hydrolyzed and thereby rendered inactive by penicillinase, an enzyme present in some resistant bacteria. The mass of this enzyme in Staphylococcus aureus is 29.6 kd. The amount of penicillin hydrolyzed in 1 minute in 10 ml solution containing 10–9 g of purified penicillinase was measured as a function of the concentration of penicillin. Assume that the concentration of penicillin does not change during the assay. [Penicillin] µM Amount hydrolyzed (nanomoles) 1 0.11 3 0.25 5 0.34 10 0.45 30 0.58 50 0.61 a) Plot V0 versus [S] and 1/V0 1/[S]. Does penicillinase appear to obey Michaelis-Menten kinetics? b) What is the value of KM? c) What is the value of Vmax? d) What is the turnover number of penicillinase under these conditions?arrow_forwardA multi-enzyme complex Is made up of three polypeptide chains, A, B and C. A is associated with decarboxylase activity; B is a transacetylase, while C is a dehydrogenase. When the protein was placed in a nonpolar solvent, then run in PAGE, two protein bands were observed. Enzyme assays showed that one protein band exhibited decarboxylase activity while the other has both transacetylase and dehydrogenase activities. When the protein was also placed in an aqueous solvent at pH 5.0, then run in electrophoresis, two protein bands were also detected. Further enzyme assays also showed that one protein band exhibits transacetytase activity while the other has both decarboxylase and dehydrogenase activities. a. What types of non-covalent interactions are possible between A, B and C? b. Addition of urea, a reducing agent gave 4 bands in the PAGE profile with a subsequent loss of decarboxylase activity. What could be the reason for the observed result? Explain briefly in terms of the structure…arrow_forward
- The objective is to study a novel protease P isolated from the digestive tract of an Amazonian insect. This protease can exist into two forms Pi and Pa which have identical amino acid sequences (both of 80 kDa). However, only Pa shows proteolytic activity. To better understand the activation mode of Pi (inactive form) in Pa (active form), the following experiment was done using DIPF. DIPF (diisopropylphosphofluoridate) is a well-known irreversible inhibitor of serine proteases. It reacts with the catalytic serine residue of the active site of proteases as shown below: Enzyme -CH₂OH + CH(CH3)2 O F-P=0 O CH(CH3)2 Diisopropylphospho- fluoridate (DIPF) Enzyme -CH,—O CH(CH3)2 O <=0 O CH(CH3)2 DIP-Enzyme Both proteases Pa and P₁ were incubated with 32P-DIPF for 30 min at 37°C, and then dialysed to remove excess of unreacted radiolabelled reagent. The two proteases were then analyzed in Sodium Dodecyl Sulphate-Polyacrylamide Gel Electrophoresis (SDS-PAGE), with and without 2-mercaptoethanol.…arrow_forwardTo approximate the concentration of enzymes in a bacterial cell, assume that the cell contains equal concentrations of 1,000 different enzymes in solution in the cytosol and that each protein has a molecular weight of 100,000. Assume also that the bacterial cell is a cylinder (diameter 1.0 μm, height 2.0 μm), that the cytosol (specific gravity 1.20) is 20% soluble protein by weight, and that the soluble protein consists entirely of enzymes. Calculate the average molar concentration of each enzyme in this hypothetical cell.arrow_forwardTwo-dimensional gel electrophoresis of proteins in a cell extract provides a qualitative way to compare proteins with respect to intra- cellular abundance. Describe a quantitative approach to the deter- mination of number of molecules of an enzyme per cell.arrow_forward
- One of your colleagues has obtained a sample of muscle phosphorylase b that is known to be relatively inactive. She has approached you for advice on how to set up an appropriate assay. She has the following items available, not all of which are appropriate for this study. Help her out by selecting the items that she should use and what their purpose is in the assay, and then explain why each of the other items would not be useful. 1. 100 UM AMP 2. 100 UM GTP 3.100 uM glucose 4. 100 uM glucose 6-phosphate 5. Branched glycogen 6. Amylose (i.e. unbranched glycogen) 7.50 mM HEPES buffer, pH 7.5 8. 50 mM potassium phosphate buffer, pH 7.5 Write out a short explanation for each of the above items, and upload your answers by the due date.arrow_forwardInhibitors of acetylcholinesterase, such as edrophonium, are used to treat Alzheimer’s disease. The substrate for acetylcholinesterase is acetylcholine. Structures are attached. What kind of inhibitor is edrophonium? Explain. Can inhibition by edrophonium be overcome in vitro by increasing the substrate concentration? Explain. Does this inhibitor bind reversibly or irreversibly to the enzyme? Explain.arrow_forwardIdris has successfully extracted enzymatic proteins from the fish viscera (intestines and stomach). After homogenization and centrifugation, he managed to pool the crude enzyme extract. He is characterizing the enzymes. Please help Idris by answering the followingquestions:The experiments I conducted showed that one of the enzymes was successful in degrading casein.(a). Which family of enzyme is it from?(b). What is the possible name of this enzyme and why?arrow_forward
- Two isoforms of an enzyme were discovered; isoform-1 produces a hormone that causes muscle spasms and isoform-2 makes a different hormone (from the same substrate) that lowers cholesterol levels. a) What strategy would you employ as a medicinal chemist to develop a drug that prevents muscle spasms without raising cholesterol levels? The active sites of isoform-1 and -2 are the same except isoform-1 has a cysteine residue and isoform-2 has a phenylalanine residue at that same position. b) What two approaches would you take for designing a muscle spasm drug without a cholesterol level increase side effect?arrow_forwardAn experiment was carried out to measure the reaction rate of hydrolysis of acetylcholme (substrate) with serum enzymes (Eadie, 1949). In the experiment, two experiments were conducted, namely experiment 1 without using a prostigmine inhibitor and experiment 2 using a prostigmine inhibitor at 1.5 x 10^-7 mol/l. the data obtained are: a. Is prostigmine competitive or noncompetitive inhibitor? b. determine the value of km and rmax for the two experiments, comparearrow_forwardA. Lineweaver-Burk plot of the enzyme with increasing amounts of substrate in the absence or the presence of the inhibitor is shown below. Graph A : x-intercept Graph B : x-intercept = - 0.012, y-intercept = 0.8 Graph C : x-intercept = - 0.027, y-intercept = 0.8 Graph D : x-intercept = - 0.039, y-intercept = 0.8 - 0.007, y-intercept = 0.8 Graph A 4 Graph B Graph C Graph D 1 -0,04 -0,02 0,00 0,02 0,04 1/[Substrate] (uM) (i) Which graph indicates an enzymatic reaction without inhibitor? (ii) Which type of inhibitor is it? Briefly explain. (iii) Which graph indicates the highest concentration of inhibitor? (iv) Calculate the Vmax and Km of the graph showing an enzymatic reaction with the lowest concentration of inhibitor. Show the steps of calculation and unit in your answers. Keep 2 decimal places in your answers. 1/Rate (umol/min)arrow_forward
- Biology: The Dynamic Science (MindTap Course List)BiologyISBN:9781305389892Author:Peter J. Russell, Paul E. Hertz, Beverly McMillanPublisher:Cengage Learning
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