BIOCHEMISTRY

• Amino Acids


  - Found in proteins

  - amino group, carboxylic acid, hydrogen atom, and R group attached to a central alpha carbon

  - chiral (L) except glycine

  - (S) configuaration except cysteine

  - join via peptide bonds
• Nonpolar, nonaromatic AA


  glycine

  alanine

  valine

  leucine

  isoleucine

  methionine

  proline
• Aromatic AA


  tryptophan

  phenylalanine

  tyrosine
• Polar AA


  serine

  threonine

  asparagine

  glutamine

  cysteine
• Acidic (- charge) AA


  aspartic acid

  glutamic acid
• Basic (+ charge) AA

  lysine

  arginine

  histidine
• can amino acids react to form a covalent bond?

  yes, with the loss of water
• Alanine


  nonpolar/hydrophobic

  methyl group

  Ala (or) A

  
• Valine


  nonpolar/hydrophobic

  isopropyl group

  Val (or) V

  
• Leucine


  nonpolar/hydrophobic

  isobutyl group

  Leu (or) L

  
• Proline


  nonpolar/hydrophobic

  major exception because ring formed

  Pro (or) P

  
• Methionine


  nonpolar/hydrophobic

  sulfar group

  Met (or) M

  
• Tryptophan


  nonpolar/hydrophobic

  Trp (or) W

  
• Phenylalanine


  nonpolar/hydrophobic

  phenyl group

  Phe (or) F

  
• Isoleucine


  nonpolar/hydrophobic

  sec-butyl group

  Ile (or) I

  
• Glycine


  polar/uncharged

  most simple, achiral, H group

  Gly (or) G

  
• Serine


  polar/uncharged

  hydroxyl group

  Ser (or) S

  
• Asparagine


  polar/uncharged

  amide bond

  Asn (or) N

  
• Glutamine


  polar/uncharged

  Gln (or) Q

  
• Threonine


  polar/uncharged

  methyl group

  Thr (or) T

  
• Cysteine


  polar/uncharged

  SH group, very functional and responsible for putting whole proteins together

  Cys (or) C

  
• Tyrosine


  polar/uncharged

  phenyl group

  Try (or) Y

  
• Aspartic acid


  Acidic (-)

  Asp (or) D

  
• Glutamic acid


  Acidic (-)

  Glu (or) E

  
• Lysine


  Basic (+)

  positive charge on NH3

  butyl group

  Lys (or) K

  
• Arginine


  Basic (+)

  Arg (or) R

  
• Histidine


  Basic (+)

  often used as a buffer

  amidisole ring

  His (or) H

  
• Neurotransmitters/Hormones that are amino acids

  GABA, Epinephrine, Histamine, Serotonin
• what kind of acids are amino acids?

  weak polyprotic acids

  - amphoteric

  - acidic pH: fully protonated

  - basic pH: fully protonated

  - neutral pH: zwitterion
• Explain a peptide bond formation

  condensation (dehydration rxn)

  - nucleophilic amino group attacks electrophilic carbonyl group.

  - peptide bonds broken by hydrolysis
• structural proteins


  collagen, elastin, keratin, actin, tubulin
• motor proteins


  capable of force generation though a confomational change, includes myosin, kinesin, dynein.
• binding proteins


  bind a specific substrate, either to sequester it in the body or hold its concentration at steady state
• cell adhesion molecules (CAMs)


  bind cells to other cells or surfaces.

  - cadherins, integrins, selectins
• enzyme-linked receptors


  participate in cell signaling through extracellular ligand binding and initiation of second messenger cascades
• G protein-coupled receptors


  have a membrane-bound protein associated with a trimeric G protein. Initiate second messenger systems
• ligases


  join two large biomolecules
• isomerases


  catalyze the interconversion of isomers, including constitutional and stereoisomers
• lyases


  catalyze cleavage without the addition of water and without the transfer of electrons. Reverse reaction is synthesis and usually more biologically important.
• hydrolases


  catalyze cleavage with the addition of water