Allosteric regulation of the state of adenylylation of glutamine synthetase in permeabilized cell preparations of Escherichia coli. Studies of monocyclic and bicyclic interconvertible enzyme cascades, in situ.

the protein components of the cascade system that regulate glutamine synthetase activity in Escheri&ia coli are retained in cells rendered permeable to small molecules by treatment with Lubrol W 2 C .All compo-' The abbreviations used are: UT-UR, the bifunctional enzyme that catalyzes the uridylylation and deuridylylation of the PI' regulatory protein; E, the state of adenylylation (i.e. the average number of adenylylated subunits/dodecameric molecule of glutamine synthetase); ATase, adenylyltransferase; UT, uridylyltransferase; UR, uri- dylyl-removing enzyme; CTAB, cetyltrirnethylammoniumbromide;AT, and ATd, the adenylylation and deadenylylation sites of ATase, respectively; PIIA and PIID, the unmodified and uridylylated forms of PI', respectively.