140 likes | 216 Views
Chapter 14 14.5 – 14.8. By: Mackenzie Stuck & Carlie Strawser . 14.5 What are uncommon amino acids?. Derived from common amino acids Post-translational modification Hydroxyproline and Hydroxylysine Hydroxyl groups Found in only a few connective tissue proteins Collagen. Differences.
E N D
Chapter 1414.5 – 14.8 By: Mackenzie Stuck & Carlie Strawser
14.5 What are uncommon amino acids? • Derived from common amino acids • Post-translational modification • Hydroxyprolineand Hydroxylysine • Hydroxyl groups • Found in only a few connective tissue proteins • Collagen
Differences • Thyroxinediffers from Tyrosine • Extra iodine – containing aromatic group • Thyroid gland • Post- translational modification of tyrosine residues • Released as a hormone
14.6 How do amino acids combine to form proteins? • Amino Acids • Carboxyl and Amino Group • COO¯ group combines with – NHз+ • Product: Amide (Dipeptide) • Joined by a peptide bond • Any Two amino acids can be linked together
Additions • A third amino acid can be added • Tripeptide • Tetrapeptide • Pentapeptide • etc. etc. etc. • can contain hundreds of thousands • Proteins that have important functions in living organisms
Terms: • Shortest chains: Peptides • Long Chains: Polypeptides • Even longer: Proteins
Book: • Protein: 30 -50 amino acids • Chain: residues • Use 1 & 3 letter abbreviations • C-Terminal Amino Acids (free -COOH¯ group) • N-Terminal Amino Acid (free -NHз+ group)
14.7 What are the properties of proteins? • Continuing pattern of pertide bonds • Backbone • Six atoms on the same plane • Two adjacent peptide bonds • One can rotate • Side chains • Amino acids • Determine • Physical and chemical properties
Isoelectric Point • pH with an equal positive and negative charge • pH above • Negative charge • pH below • Positive charge
Solubility • Depends on repulsive forces • Like charges • Repel each other • No repulsive forces • clump together • reduces their solubility
14.8 What is the primary structure of proteins? • Amino acid chain • Different sequence • Allows different functions • 20 different amino acids • dipeptides • 400 possibilities • Tripeptides • 8,000 possibilities • Small proteins • 60 amino acid residues • 20 ^ 60
Sequence to Function • Sequence usually determines the function of the protein • Depending on which it may or may not matter • Cytochrome C • 104 amino acid residue • Function- electron transport • 10/104 positions are different in sheep
Minor changes cause major differences • Hemoglobin • Even L change in an amino acid • Causes sickle cell anemia