Lecture 1 Flashcards
Simple building blocks
AAs, nucleotides, carbohydrates, acetate
Biological macromolecules
Proteins, DNA/RNA, Polysaccharides, Lipids
Side chain determines
Protein structure/function, electrical charge of protein
Side chain properties use
Methods for analysis, purification, identification
Aliphatic
Uncharged
Non-polar aliphatic
Gly, Ala, Val, Leu, Ile (from less hydrophobic to more hydrophobic)
Non-polar Aromatic
Phe, Tyr, Trp - Tyrosine and Trp hydrophobicity tempered by polar groups in side chains - help ID protein by UV
Uncharged polar
Thr, Ser, Asn, Gln
Acidic AA
Asp, Glu - hydrophilic usually on protein/water interface
Basic AA
His, Lys, Arg, Strongly polar, on exterior
Sulfur containing AA
Cys, Met, more hydrophilic than analogs, however Met is still quite hydrophobic. - Disulfide bonds
Proline
Constrained, aliphatic R, comparable to aliphatic AAs
Homocysteinuria
1 in 350,000. Causes lens dislocation around age 10. Fibrillin is rich in Cysteine and thus disulfide bonds that stabilize and crosslink. Sulfite oxidase deficiency also associated with lens dislocation.
Marfan’s Syndrome
Associated with lens dislocation due to fibrillin gene mutations
Optic AAs
All but Glycine, L (ours) and D (bacterial cell walls, peptide antibiotics).
L
Levorotatory
D
Dextrorotatory
Amphoteric amend this
change charge at different pH - in aq. soln, alpha carboxyl is -, alpha amine is +
Zwitterion
Dipolar molecule
Henderson Hasselbalch eq.
Used for isoelectric point pH = pKa + log([CB]/[WA])
Peptide bonds
loss of water (kickout of -OH of carboxyl)
Oligopeptides
3-10 aas
Polypeptides
11-99 AAs
Proteins (length)
100+ AAs
