Protein Biochemistry 1 Flashcards Preview

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Flashcards in Protein Biochemistry 1 Deck (21):
1

What amino acid repeats are found in collagen?

4-hydroxyproline and 5-hydroxylysine

2

Three individual units of _________ come together to form a supercoil.

collagen

3

While the importance of 4-hydroxyproline is disputed in the interactions of collagen fibers, __________ is undeniably important because it forms covalent connections.

5-hydroxylysine

4

Lysyl oxidase has been implicated in ______________.

breast cancer

5

Two enzymes are needed to create the modified amino acids in collagen: ______________.

prolyl hydroxylase and lysyl hydroxylase

6

What process does gamma-carboxylation allow?

Calcium chelation, in which calcium binds to two strands of protein

7

____________ uses ten of its gamma-carboxy groups to fold around calcium and expose non-polar groups that then anchor into membranes.

Prothrombin

8

__________ is ATP-dependent.

Ubiquination

9

Pepsin is a ___________ protease that cleaves _____________.

aspartic; N-terminal of aromatic residues

10

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

11

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

12

The aminotransferase reaction is directed by ____________.

concentration of substrates (because the reaction is reversible)

13

Ammonia is converted to a less toxic molecule: _________.

urea

14

Vitamin C is a cofactor in the enzyme ______________.

lysyl hydroxylase and prolyl hydroxylase

15

The ___________ protein degradation pathway is ATP independent.

lysosomal

16

Nitrogen can enter the urea cycle as __________ or _____________.

aspartate; ammonia

17

Which two amino acids are purely ketogenic?

Leucine
Lysine

18

Which four amino acids are both ketogenic and glucogenic?

Tryptophan
Isoleucine
Tyrosine
Phenylalanine

19

What two residues crosslink in collagen?

Lysine and hydroxylysine

20

PLP (a derivative of B6) is a cofactor for what reaction?

The aminotransferase reaction

21

Ammonia and bicarb join with ATP to form _______________.

carbamoyl phosphate

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