Contaminated Lys-C (AchroK)
Mike Jankowski (MJankowski@genetics.com)
Thu, 09 Apr 1998 16:11:21 -0500
We currently use Lysyl Endopeptidase from Achromobacter lyticus
purchased from Wako (catalog #129-02541) for peptide mapping. Over
the years, we have not had any problem with the enzyme specificity or
supply..until now. The enzyme was backordered for some time (~4
months) and the lots received since have yielded additional cleavages
not before observed with AchroK. Specifically, we have observed a
peptide that indicates by sequencing and mass spec a loss of the
c-terminal Lys (~25% of the peptide exhibits this, the remaining 75%
appears intact). Also cleavage was detected after a N-terminal Val in a
peptide. The question is ....anyone else having problems with recent lots
of AchroK (lots MSF-9241 and lot MSF-9242)? Contacts with Wako
(Japan) are proceeding slowly..but it appears they are having problems
manufacturing the enzyme, so heads up if you use AchroK.