Chemistry 30A3 Fall 2011 Labs Dr. Troendle 38

Chemistry 30A3 Fall 2011 Labs Dr. Troendle 38 - precursors...

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Chemical Biology 3OA3, September 2009 Page 38 E XPERIMENT 5 S OLID P HASE S YNTHESIS OF A P EPTIDE A MIDE 1. I NTRODUCTION 1.1 Peptides and Peptide Amides Peptides are polymers derived from amino acids and have molecular weights less than 5,000- 10,000; similar polymers with molecular weights greater than this are called proteins. The component amino acids are joined by amide bonds from the amino group of one unit to the carboxyl group of the next. In writing structures of polypeptides, the convention is to place the N-terminal amino acid on the left and the C-terminal amino acid on the right. Then the amino acids are named left to right using either their common names or their standardized three-letter or one-letter codes. During this course, we will see how peptides are made in vivo from the constituent amino acids, both on the ribosome and by non-ribosomal peptide synthetases, and relate these processes to chemical synthesis. Peptides have a plethora of biological activities, and are also the
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Unformatted text preview: precursors for a range of drugs such as the cyclic immunosuppressant cyclosporine. Slight variations on linear peptides are common, and one such example is the peptide amides, where the carboxy terminus is amidated, i.e. the molecule ends in C(=O)NH 2 rather than C(=O)O-. Amongst other things, this terminus changes from an anionic functionality to a neutral one, thereby altering the total net charge on the peptide, and consequently altering the biological activity of the compound drastically. Examples of peptide amides include: enkephalinamide, a super-active analog of Met-enkephalin; and dermorphin, a hepta-peptide amide first isolated from the skin of South American frogs which is a natural opiate. It binds as an agonist with high potency and selectivity to mu Opioid receptors. Dermorphin is about 30-40 times more potent than morphine but less likely to produce drug tolerance and addiction. Dermorphin has the structure H 2 N-Tyr-D-Ala-Phe-Gly-Tyr-Pro-Ser-C(=O)NH 2 ....
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This note was uploaded on 01/08/2012 for the course CHM 30A3 taught by Professor Ricktroendle during the Fall '11 term at UNF.

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