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Topic: Proteins and PI  (Read 3796 times)

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Offline asday7gas

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Proteins and PI
« on: April 22, 2016, 09:01:48 AM »
Hi, I have two questions that interest me related of proteins and PI:

1) Phosphorylation is a modification after the translation of of proteins. The addition of molecular mass protein X after phosphorylation is 80Da, when only a part (!) Of the molecules of the protein takes to phosphorylation.
Is it true that you can identify phosphorylation through differences in pI of the protein phosphorylated and non-phosphorylated?

2) Is it correct to say of proteins may pass a greater distance in SDS PAGE If the PI are lower, even that the Mw (Dalton kilobytes) bigger?

Thank you very very much!

Offline Babcock_Hall

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Re: Proteins and PI
« Reply #1 on: April 22, 2016, 09:30:15 AM »
Welcome to the forum.  It is a forum policy that you must show your attempt to answer a question before we can help you.  Perhaps a good way to start is for you to define pI and perhaps discuss how pI and amino acid composition are related.

Offline Babcock_Hall

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Re: Proteins and PI
« Reply #2 on: April 23, 2016, 09:32:54 AM »
If a polypeptide has a large number of basic residues, does this affect the pI.  What about a large number of acidic residues?

Offline Babcock_Hall

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Re: Proteins and PI
« Reply #3 on: September 26, 2016, 12:09:51 PM »
@OP,
One can see the difference in mobility in native PAGE and ion-exchange HPLC, among other techniques.

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