Flashcards in Protein Biochemistry 1 Deck (21):
What amino acid repeats are found in collagen?
4-hydroxyproline and 5-hydroxylysine
Three individual units of _________ come together to form a supercoil.
While the importance of 4-hydroxyproline is disputed in the interactions of collagen fibers, __________ is undeniably important because it forms covalent connections.
Lysyl oxidase has been implicated in ______________.
Two enzymes are needed to create the modified amino acids in collagen: ______________.
prolyl hydroxylase and lysyl hydroxylase
What process does gamma-carboxylation allow?
Calcium chelation, in which calcium binds to two strands of protein
____________ uses ten of its gamma-carboxy groups to fold around calcium and expose non-polar groups that then anchor into membranes.
__________ is ATP-dependent.
Pepsin is a ___________ protease that cleaves _____________.
aspartic; N-terminal of aromatic residues
Trypsin and chymotrypsin are both __________ proteases that attack the ________, but chymotrypsin cleaves __________ amino acids while trypsin cleaves ___________ amino acids.
serine; C-terminus; aromatic and nonpolar; basic
Aminotransferases require the cofactor __________.
pyridoxine, which "holds" the amino group during transfer (note: it is a phosphorylated version); even in a rested state, PLP forms a Schiff base with the aminotransferases
The aminotransferase reaction is directed by ____________.
concentration of substrates (because the reaction is reversible)
Ammonia is converted to a less toxic molecule: _________.
Vitamin C is a cofactor in the enzyme ______________.
lysyl hydroxylase and prolyl hydroxylase
The ___________ protein degradation pathway is ATP independent.
Nitrogen can enter the urea cycle as __________ or _____________.
Which two amino acids are purely ketogenic?
Which four amino acids are both ketogenic and glucogenic?
What two residues crosslink in collagen?
Lysine and hydroxylysine
PLP (a derivative of B6) is a cofactor for what reaction?
The aminotransferase reaction