Lecture 39 – Chapter 26 : Lipids • Phospholipids and the lipid bilayer • Prostaglandins • Terpene biosynthesis and examples Lecture 39 – Chapter 27 : Amino acids and nucleic acids • Amino acids – definition and structure • Acid-base behaviour – zwitterions • Synthesis of amino acids • Synthesis of peptides
Fatty acid biosynthesis O S ACP H 3 C reduction "Claisen" O O OH O S ACP S ACP H 3 C H 3 C O O NADPH S ACP O S -acetoacetyl-ACP S -3-hydroxybutanoyl-ACP elimination O O reduction S ACP S ACP H 3 C H 3 C NADPH, H 3 O + S -butanoyl-ACP S -2-butenoyl-ACP carbon chain extended by 2, can go up to C16, C18, C20 iteratively
Phospholipids and the lipid bilayer O O n H H phosphatidylcholine O H O n O O P O O N
Prostaglandins O O O HO OH OH HO HO OH OH prostaglandin E 1 prostaglandin F 1 α α OH O arachidonic acid
Terpene biosynthesis and examples OH Vitamin A β -Carotone β OPP (-H+) OPP OPP dimethylallyl isopentyl Geranyl pyrophosphate pyrophosphate pyrophosphate
Transfer of information in protein expression mRNA Protein transcription translation Double-stranded DNA
Chapter 27 – amino acids and nucleic acids X-ray crystal structure of peanut lectin bound to C -lactose (Kishi et. Al.)
Proteins are made up of α α -amino acids O NH 2 OH O H 2 N OH H 2 N NH 2 OH N O O H glycine glutamine (achiral) tryptophan (polar sidechain) (non-polar sidechain) O NH 2 N HO OH OH NH 2 O O HN glutamic acid histidine (acidic sidechain) (basic sidechain
α -amino acids exist as zwitterions α O O O H 3 N NH 3 O N H • Important when considering structure at different pH • Useful for separating amino acids and peptides by SDS-PAGE
Synthesis of amino acids Hell-Volhardt-Zelinsky O O NH 3 in H 2 O O OH Br NH 3 racemic syntheses Strecker Synthesis O H H 3 O + , ∆ ∆ O NH 4 Cl O CN H NaCN NH 2 NH 3
Wednesday • Chapter 27 – Amino acids, peptides, proteins and nucleic acids • Labs – clean up and check out
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