7.2 Proteins Flashcards
What are the two covalent bonds in proteins?
peptide bond
disulfide bridges
What is a peptide bond?
covalent bond formed between the carboxyl group of one amino acid and the alpha-amino group of another amino acid
What is a disulfide bridge?
covalent bond between the cysteine R-groups
What is DCC coupling?
method used to synthesize polypeptides in the lab
What causes the peptide bond to be rigid and planar?
resonance delocalization of the nitrogen’s electrons to the carbonyl oxygen giving substantial double bond character to the bond between carbonyl carbon and nitrogen
What are two means of accelerating the rate of peptide hydrolysis?
strong acids
proteolytic enzymes
What is acid hydrolysis?
cleavage of a protein into its constituent amino acids with strong acid and heat
Which method of accelerating the rate of peptide hydrolysis is specific and which is nonspecific?
specific = proteolytic enzymes
nonspecific = strong acid
What is cystine?
when a cysteine is bonded to another cysteine
What is denaturation?
the process of disrupting a protein’s shape without breaking peptide bonds
What can cause denaturation?
pH
temperature
salt concentration
urea
What forms the primary structure of a protein?
peptide bonds among amino acids
What forms the secondary structure of proteins?
hydrogen bonding between the NH and CO backbones
What are the two common motifs for the secondary structure of proteins?
alpha helix
beta pleated sheet
What forms the tertiary structure of proteins?
interactions of R-groups with each other and the solvent
