LS5002 Proteins and Metabolism Workbook - Enzymology, Protein Structure and Protein Purification


Added on  2019-09-26

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Faculty of Science, Engineering and ComputingDepartments of Biomolecular Sciences and Applied &Human SciencesLS5002 Proteins and MetabolismEnzymology, Protein Structure and Protein PurificationWorkbookInstructions to CandidatesThis paper contains THREE QUESTIONSThese questions are designed to parallel the teaching delivered in Teaching Block 1,weeks 1 to 9. This workbook represents the major assessment of the material(Enzymes, Protein Structure and Protein Purification), which will not be covered bythe end of module examination.Submission:Deadline: 23:59 on Thursday 6th December 2018Submission of the completed workbook will be to an electronic submission box onCanvas. The submitted script should be a single Word document with any figuresembedded into the document.

Question 1: Enzymes(a)Why are enzymes vital for living organisms? Include in your answer fourproperties of enzymes to illustrate your answer.(3 marks)Enzymes are biological catalysts that are essential for speeding up and activating biological reactions within living organisms, where without the enzyme may have taken a long time to occur or may not have occurred at all. Enzymes catalytic power is greater than any existing chemical catalysts, resulting into tremendous increases in reaction rates. They function in aqueous environment, which is crucial in the environment of a living organism with mild pH and temperatures. Enzymes can be regulated by other molecules usually through the process of inhibition, which changes the active site to activate or deactivate the enzyme; and because they are highly specific, the inhibitors need to be as well avoiding any inhibition to different enzymes.(b)“Enzymes are 100% protein.” Explain why this statement is incorrect,illustrating your answer with two named enzymes and their respective non-protein components.(3 marks)Not all enzymes are protein, a few commonly known exceptions are catalytic RNA’s (ribozymes). Ribozymes are ribonucleotides, which are made up of ribose sugar, a phosphate group and a nitrogenous base, where as proteins are made up of amino acids.(c)Describe, in detail, how enzymes decrease the activation energy for areaction, and how this also relates to the specificity of the enzyme.(5marks)Enzymes (d)In developing their mathematical model for invertase, what assumptions weremade by Michaelis & Menten to derive their model?(4 marks)(e)Explain the meaning of Km and Vmax, in the context of the Michaelis-Mentenmodel.(2 marks)Km is the concentration of substrate that is required to reach half of Vmax, where Vmax is the maximum rate of reaction.(f)Outline the mechanism of catalysis of chymotrypsin, with reference to theamino acid residues involved(5 marks)

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