[Biojava-dev] Problem With Isoelectric point

[yasset perez riverol]

Hi, 
 I have a problem when I execute the Isoelectrc Point
calculation for this peptides:
   ALLIDLPV
   FDIYAGTPV
   SVLLMSAEI
   PTGDTTGYLANPEEV
I all the case I receive this error :
   Error, the peptide probably contains only positive
or negative charges.

Well I try to calculate the isoelectric Point for all
the peptides with de Expasy Calculator and I obtained:
      ALLIDLPV: 
         Theoretical pI: 3.80
         Molecular weight (average): 853.07 
      FDIYAGTPV: 
         Theoretical pI: 3.80
         Molecular weight (average): 982.10 
      SVLLMSAEI: 
         Theoretical pI: 4.00
         Molecular weight (average): 962.17 
      PTGDTTGYLANPEEV: 
         Theoretical pI: 3.57
         Molecular weight (average): 1563.64

My code is this:
  OBioSeq = ProteinTools.createProtein(Sequence);
  IsoelectricPointCalc OBioIsoc = new
IsoelectricPointCalc();
  double dIsoelec = 0.0;
  dIsoelec = OBioIsoc.getPI(OBioSeq,true,true);
  
Thanks in advance
Centen of Molecular Biology.
Havana University
Cuba.


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