Lecture 2 OutlineChapter 2 Aqueous solutionsAcids and BasespHpHHenderson Hasselbalch Chapter 4 Amino Acids and PeptidesStructureChiralityNon-protein amino acidsPeptide bondWhat is the typical molarity of the H+ for maximal activity in animal tissues?i.e. ~ pH 7 However a few physiological surroundings are far from neutrality. Name one: Stomach ContentsAcid Kap KaHCOOH (formic) 1.8 x 10-43.75CH3COOH (acetic)1.74 x 10-54.76Dissociation of common acidsCH3COOH (acetic)1.74 x 10-54.76H3PO4(phosphoric) 7.25 x 10-32.14NH4+(ammonium) 5.62 x 10-109.25It is important to note that all of the pK values we have talked about refer to measurements carried out in water.In biological systems not all of the reactants operate in a purely aqueous environment.Box 2-B Acid-base balance in humans.Table 2-3 (bottom) Dissociation Constants and pK’s at 25°C of Some Acids in Common Laboratory Use as Biochemical Buffers.Page 45For reviews of pH and buffers seehttp://www.boyerbiochem.com/and go to Concept ReviewsDeep Diving ApparatusChapter 4 Voet & VoetFigure 4-1 General structural formula for α-amino acids.Page 65Figure 4-2 Zwitterionic form of the α-amino acids that occur at physiological pH values.Page 65Table 4-1 (left) Covalent Structures and Abbreviations of the “Standard” Amino Acids of Proteins, Their Occurrence, and the pK Values of Their Ionizable Groups.Page 66Table 4-1 (right) Covalent Structures and Abbreviations of the “Standard” Amino Acids of Proteins, Their Occurrence, and the pK Values of Their Ionizable Groups.Page 67Ways in Which Amino Acids Differ• Polarity• Acidity, Basicity• Aromaticity•Bulk•Bulk• Conformational Flexibility• Ability to Crosslink• Ability to Hydrogen Bond• Chemical ReactivityFigure 4-9 Greek lettering scheme used to identify the atoms in the glutamyl and lysyl R groups.Page 71Figure 4-5 Structure of cystine.Page 69cystineFigure 4-4a Structure of phenylalanine. (a) Ball and stick form.Page 69Figure 4-4b Structure of phenylalanine. (b) Space-filling model.Page 69Figure 4-3 Condensation of two α-amino acids to form a dipeptide.Page 68Figure 4-6 Titration curve of glycine.Page 70Figure 4-7 Titration curves of the enzyme ribonuclease A at 25°C.Page 71KCl concentratoion = 0.01M blue, 0.03 red, 0.15 greenFigure 4-8 The tetrapeptide Ala-Tyr-Asp-Gly.Page 71Figure 4-10 The two enantiomers of fluorochlorobromomethane.Page 72Figure 4-11 Schematic diagram of a polarimeter.Page 72Figure 4-12 Fischer convention configurations for naming the enantiomers of glyceraldehyde.Page 73Figure 4-13 Configuration of L-glyceraldehyde andL-αααα-amino acids.Page 73Figure 4-14 “CORN crib” mnemonic for the hand ofL-amino acids.Page 73Figure 4-15 Fischer projections of threonine’s four stereoisomers.Page 74Only the L-Threonine isomer is found in proteins. Isoleucine is the only other amino acid found in proteins which has 2 asymmetric centers.Ways in which an enzyme can interact with substrateInteraction of prochiral compound with enzymeFigure 4-20 Views of ethanol.Page 75Note: The conversion of the serine to selenocysteine occurs on the tRNAFigure 4-22 Some uncommon amino acid residues that are components of certain proteins.Page 77Figure 4-23: Some biologically produced derivatives of “standard” amino acids and amino acids that are not components of proteins.Page 77Figure 4-3 Condensation of two αααα-amino acids to form a dipeptide.Page
View Full Document
Unlocking...