lecturenoteschap3-10-4slides

lecturenoteschap3-10-4slides - BCMB 3100 Chapter 3 (part 1)...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 BCMB 3100 – Chapter 3 ( part 1) Diversity of protein function • Complete definition of amino acids • Memorize complete structure of 20 common 1 amino acids!!! •pK a s o f amino and carboxyl groups • Amino acids with ionizable side groups • Titration curve PROTEIN STRUCTURE AND FUNCTION Mulder (1800s): showed albumins (milk and egg) contained ____________ Berzelius (1838): named such substances ________________ 2 from Greek proteios "of first rank" Proteins recognize and ___________ many different types of molecules & ___________ most of the ____________________ necessary for life. Examples of Protein Function ____________________: enzymes increase reaction rates by 10 6 -fold; nearly all known enzymes are proteins : 3 ____________________: many small molecules and ions are transported by proteins; examples: hemoglobin, myoglobin ____________________: examples: myosin and actin (muscle movement) Examples of Protein Function ___________________: collagen (tensile strength to skin and bones) ___________________: antibodies 4 __________________________________________ ____________: example: acetylcholine receptor _________________________________: DNA binding proteins (repressors, activators, transcription factors, hormones, regulation of translation
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 WHAT ARE PROTEINS? Proteins are macromolecules made up of amino acids (____________________) -amino acids : consist of an ____________ , a _______________ , a ________________ and a distinctive __________ bonded to a carbon atom. This carbon is called the _________ b iti dj tt th b l 5 because it is adjacent to the carboxyl group. BCMB 3100 - Chapter 3 • Diversity of protein function Complete definition of amino acids • Memorize complete structure of 20 6 common amino acids!!! •pK a s o f amino and carboxyal groups • Amino acids with ionizable side groups • Titration curves & pI Amino acids in solution will be in a charged state . The amino group and/or the carboxyl group will be charged depending upon the pH. The R group may also be charged. At neutral pH amino acids are predominantly __________________ (zwitterions ) 7 • Under normal cellular conditions amino acids are zwitterions (dipolar ions): Amino group = -NH 3 + Carboxyl group = -COO - General Structure of the ionized from of an amino acid COO - NH 3 + C H Fischer Projection 8 R COO - : pKa 1.8-2.5 NH + : pKa 8.7-10.7 You MUST know this!!!
Background image of page 2
3 Fig 3.1 Two representations of an amino acid at neutral pH (a) Structure 9 (b) Ball-and stick model Amino acids are ___________ (asymmetric) due to the tetrahedral array of 4 different groups around the -carbon (glycine is an exception). Thus all amino acids except glycine can exist as enantiomers: two sterioisomer that are nonsuperimposable mirror images 10 of each other. Enantiomers of amino acids are called D (right-handed) or L (left-handed) L and D refer to absolute configuration _________________ are the only constituents of proteins Fig 3.2 Mirror-image pairs of amino acids 11 20 different amino acids are found in proteins _____________________ (side chains) that differ in size, shape, charge, hydrogen- bonding capacity & chemical reactivity 20 different amino acids found in proteins of all organisms from bacteria to humans The amino acid alphabet is at least 2 billion 12 years old The diversity of protein structure & function is due to the sequence and number of amino acids found in a protein (primary structure) It is essential that a biochemist commit to memory the structure of the 20 amino acids!
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 20

lecturenoteschap3-10-4slides - BCMB 3100 Chapter 3 (part 1)...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online