1. Insulin Produced by beta-cells in pancreas Hormone involved in regulation of blood glucose levels tells liver, muscle and fat cells to take up glucose from the blood and store it as glycogen (liver cells, muscle cells) or fat (fat cells) Liver cells Muscle cells Fat cells Class Project

2. Insulin Gene is located on chromosome 11 at locus 11p15.5 Gene ID: 3630 Gene Symbol: INS Class Project

3. B chain (30 AA) A chain (21 AA) Insulin A single gene is responsible for preproinsulin Undergoes extensive protein modifications following translation to remove the D chain and C chain regions The remaining A chain and B chain regions form insulin Preproinsulin = 106 AA Insulin = 51 AA C chain (30 AA) D chain (30 AA) Class Project

4. Insulin Can be found in protein data bank at: http://www.pdb.org/pdb/explore/explore.do?structureId=3E7Z Can also be viewed at: http://www.vivo.colostate.edu/hbooks/pathphys/endocrine/pancreas/insulin_struct.html Active form = monomer composed of A chain and B chain The A chain is composed of 21 amino acids The B chain is composed of 30 amino acids The A and B chains are held together by two disulfide bonds Inactive form (stored form) = hexamer held together by zinc ions disulfide bonds Class Project

5. Model Transcription 1.Use the RNA nucleotides to construct an mRNA copy of the preproinsulin gene (be sure to use the correct strand – the one given in the research paper) Model Translation 2.Translate the preproinsulin mRNA into a protein by using the nucleotide sequence to place the amino acids in the correct order (write the abbreviation for each amino acid on the little slip of paper) Model Protein Editing 3.Perform the edits shown in the slides Form two disulfide bonds Remove the D chain and then the C chain In Class Activity: Protein Synthesis