grades of galactose

[Tom Menees]

What grades of galactose have people found appropriate for short-term
induction of gene expression?  Sigma sells a 98% pure galactose that can
have up to 2% glucose (G 0625) and a 99% pure galactose that has no more
that 0.01% glucose (G 0750).  The grade with <0.01% glucose is >3X more
expensive.  I am growing cells in raffinose and then adding galactose to
the cultures, incubating only for an additional 4 to 7 hr, to achieve
short-term induction of gene expression.

Tom Menees
University of Missouri-Kansas City
Division of Cell Biology and Biophysics
2411 Holmes Street
Kansas City, MO 64108
tel (816)-235-1849
fax (816)-235-5218
email tmmenees at cctr.umkc.edu