protseq=raw_input("Enter protein sequence: ").upper()
charge = -0.002
AACharge = {"C":-.045,"D":-.999,"E":-.998,"H":.091,
          "K":1,"R":1,"Y":-.001}
for aa in protseq:
    charge += AACharge.get(aa,0)
print charge

This code is part of the book "Python for Bioinformatics", by Sebastian Bassi (sbassi@genesdigitales.com). Return to home page.