Amino Acids Flashcards
what are the small side chain (hydrophobic) non polar AAs?
Gly, Ala, Pro (GAP)
what are the non polar hydrophobic branched chain AA’s ?
Val, Ile , Leu , Met (MILV)
what is the non-polar (hydrophobic) aromatic side chains
Phe, Trp (TP) Toliet papaer
what are the uncharged polar side chains?
Ser, Thr, Tyr, Gln, Asn, Cys (GATTCS)
what are the negative and positive polar side chains ?
Positive- Lys, Arg, His (LAH POSTIVE)
negative- Asp, Glu (GA NEGATIVE )
what is the pKa value of -COOH TERMINAL
approx 2.2
what is the pka value of NH3 (n terminus)
9.5
what is the pka value of the phenol on tyrosine ?
10.5
what is the pka value of sulfhydryl on cysteine?
8.4
what is the pka value of the NH3 on lysine ?
10.5
what is the pka value of guandinino on arginine ?
12.5
what is the pka value of imidazole for histidine ?
6.0
what is the pka value for the carboxylic acid on aspartic acid ?
3.9
what is the pka value of the carboxylic acid on glutamic acid ?
4.1
how to calculate pi for AA with 2 ionizable groups
its is pI= pka1 + pka 2/ 2 (its the average
how do you calculate pi when theres 3 ionizable groups ?
- if the side chain is a negative group your going to use the carboxylic acid pka of 2.1 ( carbox + side chain /2
- if the side chain is a postive group you are going to use the amino group + side chain/ 2 and get the average
how to calculate fractional charge ?
- using HH equation find [A-] using the pi average as PH if there is no given ph and use the known pka values of the side chains
- if using nh3 [A-} will be positive if using COOH [A-] will be negative
- divide it by (+/-) [A-]/ (+/ -_ [A-] +1]
when is the pi = ph for amino acids
when the sum of the ionizable charges are zero
what happens when the pH of the solution is less than the pi of AA?
the overall charge will be positive
what happens if the ph of the solution is greater than the pi of the AA?
the overall charge will be negative
what type of stereochemistry do amino acids have and what structure is it based off of ?
L-configuration that is based off of L-glyceraldehyde
what happens to L-glyceraldehydy when its flipped ?
certain enzymes may not work
what are non standard animo acids ?
AAs found in other proteins that have post translational modifications
what type of bonds can cys (cysteine) do ?
di sulfide bonds
