NUR1 200 Lecture Notes - Lecture 2: Sanger Sequencing, Nucleic Acid Sequence, Methionine
10 May 2016
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Document Summary
Polypeptides linked covalently (sharing electron )= each polymer is a chain. Polypeptides linked no-covalently (none sharing electron)= each polymer is a subunit: insulin = 2 covalently linked polypeptide chains, hemoglobin = 4 no-covalently linked subunits. Enormous size range exists among biologically active oligopeptides, polypeptides and proteins: oxytocin: peptide hormone = 9aa, albumin: serum protein = 609 aa. Average molecular weight is 128, when adjusted for occurrence in proteins: meaning smaller aa are more common. One molecule of water is removed per aa during polymerization (via condensation: for each aa residue in a protein, the weight is 110 (128-18) Amino acids (aa) polymerize to form larger molecules. 2 -3-4 or + aa residues condense to form dipeptides, tripeptides, tetrapeptides, etc Condensation of aa monomers occurs by removal of: proton from the -amino group of one aa, hydroxyl from the -carboxyl group of another aa. The covalent linkage joining the two aa is called the peptide bond or peptide linkage.
