PROTEIN

• What does the primary structure of proteins refer to?

  Amino acid sequence
• What is the bond linking amino acids called?

  Peptide bond
• Which level of protein structure involves hydrogen bonding between backbones?

  Secondary
• What amino acids commonly include a β-turn?

  Glycine and Proline
• What stabilizes the tertiary structure of proteins?

  Hydrophobic interactions, ionic bonds, hydrogen bonds, disulfide bonds
• What is the quaternary structure of proteins?

  Interaction of multiple polypeptide chains
• Which protein assists in folding?

  Chaperone
• What does misfolding of proteins lead to?

  Alzheimer’s
• What do prion diseases involve?

  Misfolded proteins
• What is the zinc finger motif associated with?

  DNA binding
• What is myoglobin?

  Monomeric oxygen-binding protein
• What does the catalytic triad in serine proteases include?

  Asp, His, Ser
• After which amino acids does trypsin cleave?

  Lysine and Arginine
• After which amino acids does chymotrypsin cleave?

  Aromatic amino acids
• What does Km reflect?

  Substrate affinity
• What does a low Km indicate?

  High affinity
• What happens to Vmax with increased enzyme concentration?

  Vmax increases
• Where do ubiquitinated proteins go?

  Proteasomes
• What does calmodulin bind?

  Calcium
• What type of proteins are Ras proteins?

  GTPases
• On which amino acids does phosphorylation occur?

  Ser, Thr, Tyr
• What does denaturation affect?

  Secondary, tertiary, quaternary structure
• What is collagen?

  Triple helix
• What is keratin rich in?

  Disulfide bonds
• What are enzymes?

  Catalysts
• What does hemoglobin show?

  Cooperative binding
• What are fibrous proteins?

  Collagen, keratin
• What are globular proteins?

  Enzymes, hemoglobin
• What does the lock-and-key model describe?

  Enzyme-substrate binding
• What does the induced fit model suggest?

  Enzyme changes conformation on substrate binding
• What do allosteric enzymes show?

  Sigmoidal kinetics
• What usually involves feedback inhibition?

  End product binding to enzyme
• What are cofactors?

  Non-protein helpers for enzymes
• What does an apoenzyme plus cofactor equal?

  Holoenzyme
• What are zymogens?

  Inactive enzyme precursors
• What does enzyme turnover number (kcat) mean?

  Substrates converted per second per enzyme
• What type of enzyme inhibition competes with substrate?

  Competitive
• What type of enzyme inhibition binds elsewhere?

  Noncompetitive
• What do irreversible inhibitors do?

  Form covalent bonds
• At what pH does pepsin work best?

  Acidic pH