BIOCHEMISTRY ASSIGNMNET Scholarship Essay Example | Topics and Well Written Essays - 2750 words

BIOCHEMISTRY ASSIGNMNET - Scholarship Essay Example Sci-Tech Encyclopedia information about ion exchange McGraw-Hill Encyclopedia of Science and Technology. Copyright 2005 by The McGraw-Hill Companies, Inc Carl R. Kemnitz and Mark J. Loewen J. Am. Chem. Soc.; 2007; 129(9) pp 2521 - 2528 http://www.expasy.ch/ http://www.brenda.uni-koeln.de http://www.genome.ad.jp/dbget-bin/www_bgetec:1.5.1.34 Biochemistry Manual from http://mcb.berkeley.edu/ UniProtKB/TrEMBL Release 35.5 of 15-May-2007 UnitProt Taxonomy Browser. http://www.ebi.ac.uk/newt/display Protein Spotlight, 2004. Swiss Institute of Bioinformatics Q1. (30 marks) The following peptide, substance Z, was isolated from whale intestinal mucosa: GAKKIYPRVSACMIHGGAVIAIDMDGTDA The active peptide is amidated on the C-terminal amino acid. Draw the structure of the amidated amino acid residue. (5) The following reagents act on this peptide. Write out the products for each treatment, using the one-letter amino acid abbreviations. (6) a. Trypsin GAK---K---IYPR---VSACMIHGGAVIAIDMDGTDA b. Dansylchloride (first products) GAK---KIYPRVSACMIHGGAVIAIDMDGTDA c. Cyanogen bromide. GAKKIYPRVSACM---IHGGAVIAIDM---DGTDA Peptide Z is an inactive precursor. It is converted to the active peptide by hydrolysis with chymotrypsin. The larger product of the hydrolysis is the active peptide. Draw the structure of the active peptide. (8) GAKKIYPRVSACM---IH---GGAVIAIDM---DGTDA Q2. (30 marks) a) Read up about leucine zipper proteins and answer the following questions. Keep answers brief. - What is the characteristic structural feature of these proteins What forces keep the zipper zipped up These proteins are characterized by two helices that look like a zipper with leucine residues lining on the inside of the zipper. The hydrophobic interactions of the branched chain of the...In this way, the larger molecules of the inactive peptide would not be able to bind to the stationary phase and therefore, will be eluted first. And after this, a strong acid exchanger can be used to facilitate the dissociation of the active peptide with the stationary phase. Enzyme activity at 5 hours was measured as DA min-1 = 0.15. The protein concentration of the stock enzyme solution used for the assay of activity was 50 mg ml-1. Details of the assay are given in Q4. Assume e for the product was 800 L mol-1 cm-1 at the wavelength used, and measurements were made in a cuvette of 1 cm light path. Calculate the specific activity of the enzyme after it had been treated for 5 hours at 25o. Express your answer as mmoles product produced per minute per mg protein. Set all your calculations out clearly. Peptide Z is an inactive precursor. It is converted to the active peptide by hydrolysis with chymotrypsin. The larger product of the hydrolysis is the active peptide. Draw the structure of the active peptide. (8) - What is the characteristic structural feature of these proteins What forces keep the zipper zipped up These proteins are characterized by two helices that look like a zipper with leucine residues lining on the inside of the zipper. The hydrophobic interactions of the branched chain of the leucine residues keep the helices in place. - What is the role of the zipper in these proteins - In pri