one more - nitya

[ArchivalUser]

what is the net charge on glutamic acid at a pH 1?
a.+2
b.+1
c.0
d.-1
e.-2

[ArchivalUser]

how to calculate this

[ArchivalUser]

someone please explain this one too

[ArchivalUser]

i will try if the answser is +1
)) just kiddin i hate ph, pka, pi stuffs

b??

[ArchivalUser]

yes answer is 'b'

can u explain it please

[ArchivalUser]

please explain natya..i m confused ):

[ArchivalUser]

now nitya i am in trouble because it was a simple guess, anyway thank you for posting and i will provide explanation in a litle unless someone else will rescue me.

)))

[ArchivalUser]

Each protein has numerous charges:

Amino terminus is positively charged

Carboxy terminus is negatively charged

Amino acid side chains (R groups) may carry a charge (review acidic and basic amino acids)

The net charge on a protein is the sum of all the individual charges

The net charge varies with pH

At the pI, the protein has no NET charge: The number of positive charges is equal to the number of negative charges.

At low pH, the protein becomes more positively charged

At high pH, the protein becomes more negatively charged.

Example: Glutamic Acid
PKa (COOH) = 2.19 COOH to COO-
PKa (NH3+) = 9.67 NH3+ to NH2
Pka ® = 4.25
COOH to COO-



pH=1

COOH=0

NH3+=+

R=0
--------------
Net charge+1

[ArchivalUser]

thankyou very much sao

[ArchivalUser]

urw, nitya.