AA, Proteins, Enzymes (Biochem) Flashcards
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
AA that have R-groups with - charge at physiologic pH
aspartic acid and glutamic acid
AA that buffers well in proteins at physiologic pH
Histidine
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
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
Positive Nitrogen balance associated with
- growth
- pregnancy
- recovery phase of injury/surgery
- recovery from condition associated with negative nitrogen balance
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)
Do competitive or non-competitive inhibitor increase Km?
Competitive inhibitors increase Km
How do you change Vmax?
add more enzyme
noncompetitive inhibitors
- no effect on Km
- DECREASE Vmax
Km =
substrate concentration at which enzyme is at 1/2 Vmax
Competitive inhibitors
- increase Km
- no effect on Vmax
This enzyme is a major precursor in gluconeogenesis
Alanine (nonpolar)
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
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