The heating of protein preparations of mesophi
lic organism (e.g.,
E. coli) producesthe ob
literation of a
ll so
lub
le mu
ltimeric proteins from this organism. In this way, ifa mu
ltimeric enzyme from a thermophi
lic microorganism is expressed in thesemesophi
lic hosts, the on
ly
large protein remaining so
lub
le in the preparation afterheating is the thermophi
lic enzyme. These
large proteins may be then se
lective
lyadsorbed on
low
ly activated anionic exchangers, enab
ling their fu
ll purification in justthese two simp
le steps. This strategy has been app
lied to the purification of an
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lactosidase and a
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le">-ga
lactosidase from
Thermus sp. strain T2, both expressed in
E. coli, achieving the a
lmost fu
ll purification of both enzymes in on
ly these two simp
lesteps. This very simp
le strategy seems to be of genera
l app
licabi
lity to the purificationof any thermophi
lic mu
ltimeric enzyme expressed in a mesophi
lic host.