To: ABRF questions
cc:
Subject: AAA
Hello abrf'ers
We have a serious problem concerning determination of the exact
concentration of a protein sample. Up to now we always used AAA for this
purpose. We perform PTC-analysis on a 420A/H (PE-ABI) automatic
hydrolysis and ptc-derivatisation unit.
Calibration is done by the "hydrolysis test peptide (PE-ABI, part
no.400909) without the addition of a internal calibrant. The last few
months we observed a real problem in the solubility of this hydrolysis test
peptide. The result of this is that we normally have a very good
compositional error for proteins (average below 10% error) BUT we are not
sure anymore about the exact concentration of the measured protein batch.
We contacted already the people from PE-ABI and they send us different
hydrolysis test peptide batch numbers but the problem still exist.
So, my questions :
1. Has anyone already observed this problem with the hydrolysis test
peptide on the 420A/H machine?
2. Is there an alternative compound available as calibration compound in
AAA?
2. Is there a better way to determine the EXACT concentration of a protein
batch? (no coloring method like BRADFORD, BCA, ...)
Thanks in advance
Jos Raymackers, Ing.
e-mail (innogenetics) : josray@innogenetics.be
e-mail (home) : jos.raymackers@village.uunet.be
INNOGENETICS NV
Industriepark 7 box 4
9052 Zwijnaarde Ghent
Belgium
tel. (office) : 0032-9-2410778
tel. (lab) : 0032-9-2410775
fax. : 0032-9-2410907