Flashcards in AA, Proteins, Enzymes (Biochem) Deck (31)
Loading flashcards...
1
AA that have R-groups with + charge at physiologic pH
- Arginine and Lysine (both are found in histones)
- histidine has a + charged R group at neutral pH, that is found at the active site of enzymes
2
AA that have R-groups with - charge at physiologic pH
aspartic acid and glutamic acid
3
AA that buffers well in proteins at physiologic pH
Histidine
4
Essential AA
P - phenylalanine (NOT PROLINE)
V - valine
T - threonine (NOT TYROSINE)
T - tryptophan (NOT TYROSINE)
I - isoleucine
M - methionine
H - histidine
A - arginine (only essential in kids*)
L - leucine
L - lysine
*kids have + N balance and need more N
5
Negative Nitrogen balance associated with
- protein malnutrition (kwashiorkor)*
- dietary deficiency of even one essential AA
- starvation
- uncontrolled diabetes
- infection
* Don't confuse with marasmus = chronic deficiency of calories. These patients do not present with edema like patients with kwashiorkor
6
Positive Nitrogen balance associated with
- growth
- pregnancy
- recovery phase of injury/surgery
- recovery from condition associated with negative nitrogen balance
7
a child with PKU has how many essential AA?
- Normal adults only need 9 (arginine is only essential in kids)
- normal kids only need 10 (arginine)
- kids with PKU need 11 (also need tyrosine)
8
Do competitive or non-competitive inhibitor increase Km?
Competitive inhibitors increase Km
9
How do you change Vmax?
add more enzyme
10
noncompetitive inhibitors
- no effect on Km
- DECREASE Vmax
11
Km =
substrate concentration at which enzyme is at 1/2 Vmax
12
Competitive inhibitors
- increase Km
- no effect on Vmax
13
This enzyme is a major precursor in gluconeogenesis
Alanine (nonpolar)
14
AA with Nonpolar, aliphatic side chains
- glycine (gly)
- alaine (Ala)
- valine (Val)
- leucine (Leu)
- ieoleucine (Ile)
- proline (Pro) (has secondary amine)
6 AA with Nonpolar, aliphatic side chains
* VP GAILe
- A is not Arginine
- L is isoleucine, not lysine
15
Hartnup's Disease
- AR
- affects absorption of non polar AA
- tryptophan not absorbed therefore can't make serotonin, melatonin, niacin
- symptoms: photosensitivity, nystagmus, tremor, ataxia (neurological)
- Tx: high protein diet
16
AA with aromatic side chains
3 total:
- phenylalanine (Phe)
- tyrosine (Tyr)
- tryptophan (Trp)
- tryptophan used to make serotonin, melatonin, niacin
- tyrosine is used to make T3, T4, and melanin
17
AA used to make catecholamines T3, T4 and precursor to melanin
Tyrosine
18
AA with polar, uncharged R groups
- serine (Ser)
- threonine (Thr)*
- cysteine (Cys)
- asparagine (Asn)
- glutamine (Gln)
- methionine (Met can be considered nonpolar or polar bc has S)
* Threonine target of O-glycosylation in Golgi
*STAG MC
- A = asparagine
- T = threonine
19
which AA is the precursor to NO
- Arginine
- Remember: Essential AA in kids
20
Body uses which AA to carry NH3 in blood
Glutamine
21
AA that contain Sulfur
- Cysteine and Methionine
- targets of N-glycosylation that begins in ER
22
protein breakdown occurs in 2 locations
1. lysosomal proteases digest endocytosed proteins
2. large cytoplasmic complexes (proteasomes) digest older or abnormal proteins that have been covalently tagged with ubiquitin for destruction
23
Which AA are precursors for catecholamines
phenylalanine and threonine
(catecholamine ex: Norepinephrine, Epinephrine, Dopamine)
24
Hydrophilic AA
- Positively charged AA (3), Negatively charged AA (2), Polar uncharged AA (6)
- 11 total: aspartate, glutamate, lysine, arginine, histidine, serine, threonine, cysteine, methionine, asparagine, glutamine
25
Which are branched-chain AA whose metabolism is abnormal in maple syrup urine disease?
valine, leucine and isoleucine (all nonpolar)
26
which AA is a secondary amine whose presence in a protein disrupts normal secondary structure?
proline
27
hydrophobic AA
9 total: glycine, alanine, valine, leucine, isoleucine, proline, phenylalanine, tyrosine, tryptophan
28
Which AA can form serotonin and niacin
Tryptophan
29
- Is Hartnup's disease AD or AR?
- symptoms? what causes them?
- AR
- tryptophan not absorbed therefore can't make serotonin, melatonin, niacin
- symptoms: photosensitivity, nystagmus, tremor, ataxia (neurological)
30
