Amino acids and proteins Flashcards
What are the AAs with aliphatic side chains?
Glycine
Alanine
Valine
Leucine
Isoleucine
What AAs have -OH groups in their side chains?
Serine
Threonine
Tyrosine
What AAs have side chains with sulfur atoms?
Cysteine
Methionine
What AAs have acidic side chains?
Aspartic acid
Glutamic acid
Asparagine
Glutamine
What AAs have basic side chains?
Arginine
Lysine
Histidine
What AAs have side chains with aromatic rings?
Histidine
Phenylalanine
Tyrosine
Tryptophan
What AA is actually an imino acid and why?
Proline - secondary nitrogen part of ring
What AAs have nonpolar side chains?
Glycine
Alanine
Valine
Leucine
Isoleucine
Phenylalanine
Tryptophan
Methionine
Proline
What AAs have polar side chains?
Serine
Threonine
Tyrosine
Cysteine
Asparagine
Glutamine
Aspartic acid
Glutamic acid
Lysine
Arginine
Histadine
What AA acts as a buffer at physiologic pH?
Histidine
What are the essential AAs?
Arginine
Valine
Histidine
Leucine
Isoleucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
What are the nonessential AAs?
Glycine
Alanine
Serine
Cysteine
Aspartic acid
Asparagine
Glutamic acid
Glutamine
Tyrosine
Proline
What are the glucogenic AAs and what do they do?
Serve as precursor for formation of glucose or glycogen
Glycine
Alanine
Serine
Cysteine
Glutamic acid
Glutamine
Proline
Histidine
Arginine
Methionine
Valine
Aspartic acid
Asparagine
What are the ketogenic AAs and what do they do?
Precursor for acetyl CoA
Leucine
Lysine
What AAs are both glucogenic and ketogenic?
Phenylalanine
Isoleucine
Tryptophan
Tyrosine
Threonine
What is the equation for pKa and what is it?
pKa = -logKa
pKa is the pH where the acidic group is half dissociated
What is isoelectric pH (pI)?
Zwitterion form of AA - half +ve and half -ve
Net charge is zero
What is the bond found in proteins?
Peptide bond between amino group of one protein and carboxyl group of another
What bonds stabilize alpha-helices?
H-bonds
What AAs do not favor alpha helix and why?
Proline - irregular structure as imino acid
Glycine - small size
Large number of charged or bulky R groups
What is conformation?
Spatial relationship of every atom in a molecule
What determines tertiary structure?
Primary structure
What bonds stabilize tertiary structure?
Covalent - disulfide
Noncovalent - h bond, hydrophobic interactions, ionic bonds
