Flashcards in Amino Acids, Peptides, and Protein I Deck (45)
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1
Hydrophobic and non-polar amino acids
Valine
Isoleucine
Leucine
Methionine
Phenylalanine
Tryptophan
Cystine
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2
hydrophilic and polar amino acids
argenine
lysine
aspartate
glutamate
asparagine
glutamine
3
acidic amino acids
aspartate
glutamate
4
basic amino acids
lysine
arginine
histidine
5
what may interactions between positive and negative R groups form?
salt bridge important for stabilization in proteins
6
what is a disulfide bond?
covalent linkage between two sulfer atoms specifically between cystine residues (thiol groups)
7
which amino acid has a sulfur bond but cannot participate in a disulfide bond?
methionine
8
where are disulfide bonds usually found within a folded protein?
on the inside because they are hydrophobic
9
what are the 6 major post-translational modifications that we need to know?
1. hydroxylation of proline
2. carboxylation of glutamate
3. modification by acetylation or methylation
4. glycosylation
5. reversible phosphorylation/dephosphorylation
6. ubiquination
10
what adds a hydroxyl group to proline residue?
prolyl hydroxylase
11
what is the predominate secondary structure in collagen and how is it formed?
proline helix
formed by multiple prolines and hydroxyprolines in a row
12
what is the cofactor of prolyl hydroxylase?
vitamin C
13
what disease results as a lack of vitamin C and which structure is affected?
scurvy, loss of integrity in connective tissues becase lack of proline hydroxylation
14
which enzyme adds a carboxyl group to the side chain of glutamate?
Gamma-glutamyl carboxylase
15
what is the co-factor of carboxylation of glutamate?
vitamin K
16
where is carboxylation of glutamate mostly found?
within clotting factors
17
what will a lack of vitamin K cause in regards to carboxylation of glutamate?
hemorrhage
18
how does waafarin work?
blood thinner that prevents clotting by inhibiting activity of gamma-glutamyl carboxylase
19
where does acetylation by HATs usually occur?
lysine residues of free tails of histones
20
where does methylation usually occur and by which enzyme?
lysine and arginine residues on histones by methyltransferases
21
what type of inhibitor is Vorinostat?
HDAC inhibitor
22
what is the mechanism of Vorinostat?
prevents removal of acetyl groups from histones. Tumors usually use deacetylation to repress tumor suppresor genes.
23
what is glycosylation?
attaching glycans (sugars) to proteins
24
what are the 4 types of glycans?
1. N-linked glycans
2. O-linked glycans
3. phospho-glycans
4. C-linked glycans
25
what amino acids to N-linked glycans attach to?
asparagine and arginine side chains
26
what amino acids to O-linked glycans attach to?
serine, threonine, tyrosine, hydroxylysine, hydroxyproline side chains
27
where do phospho-glycans attach?
phosphate of phospho-serine
28
where do C linked glycans attach?
carbon on tryptophan side chain
29
True of False
Glycosylation makes protein more polar
true
30
