pI of TGF-beta

Keith Robison robison1 at husc10.harvard.edu
Sat Nov 20 10:35:23 EST 1993

mack at fcs260c.ncifcrf.gov (Joe Mack) writes:

>In article <3559 at rc1.vub.ac.be> pjdebles at vub.vub.ac.be (Pieter De Bleser) writes:
>>Dear bionetters,
>>Does anyone know the pI of TGF-beta, or has a pointer to where I can
>>find this data?

>Find a place that has the GCG set of programs and databases. Get an account.
>Findout about all the neat programs thay have for protein peopple and molecular
>biologists. Use the program "ISOELECTRIC".

Ahh, but did the original poster want the PREDICTED pI or the ACTUAL pI?
Particularly with the multitude of post-translational modifications in
mammalian cells (and especially since many of these involve derivatizing
charged amino acid side chains or adding charged moieties), it is an
important distinction.

Keith Robison
Harvard University
Department of Cellular and Developmental Biology
Department of Genetics / HHMI

robison at biosun.harvard.edu 

P.S.  Taking into account both the N-terminal peptide processing and
      the observed blockage of the mature protein's N-terminus to 
      Edman degredation (and assuming the blocking group is non-charged),
      the pI of the major isoform of TGF-beta (Human) is predicted to
      be 4.75 using the 'iso' program from my MOLBIO++ library.

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