Is there a way of quantifying a peptide which is both simple and accurate?
Weighing is often a problem due to crystallization waters and often the
available peptide is insufficient. We have tried calculating the global
peptide bond extinction coefficient, used the bicinconinic acid and
ninhydrin assays, used
the method of Waddel and others, and results always vary considerably, and
do not agree too well with estimates based on internal standards (Tyr or
Trp), when these are available. We have also tried leaving the Fmoc group on
to provide the standard, and then removing it, but its messy and apparently
sometimes results in peptide degradation. Its a real problem. Amino-acid
analysis is claimed to be the most accurate method, but I have been told it
has problems as well. Can anyone suggest alternative methods?
Alex Tossi
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Dr. Alessandro Tossi
Department of Biochemistry
University of Trieste
Via Giorgieri 1
I-341227
ITALY
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email: tossi@bbcm.univ.trieste.it
phone - 39 040 6763673
fax - 39 040 6763673
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