[Regulation of the supramolecular structure and the catalytic activity of gamma-glutamyltransferase in the reversed micelle system].
Regulation mechanisms of the supramolecular structure and the catalytic activity of a heterodimeric enzyme, gamma-glutamyltransferase, in the system of Aerosol OT (AOT) reversed micelles in octane have been studied. gamma-(3-carboxy-4-nitro)-glutamic acid anilide (L- and D-isomers) and glycylglycine were used as substrates to explore the enzyme-catalyzed hydrolase, autotransferase, and transferase reactions. For all types of reactions, the catalytic activity of gamma-glutamyltransferase as a function of the hydration degree has a shape of curves with three optima. The optima of the catalytic activity were detected at hydration degrees [( H2O]/[AOT] = 11, 17, and 26) when radii of the micelle's inner cavity are commensurate with the light and heavy subunits (Mr 21,000 and 54,000, respectively) of gamma-glutamyltransferase as well as with the dimer (Mr 75,000). As ultracentrifugation the change in hydration degree caused a reversible dissociation of the enzyme to the light and heavy subunits. Both subunits catalyze the hydrolase and transferase reactions, whereas the autotransferase activity was detected only for the heavy subunit. Dependencies of catalytic activities of the subunits on the hydration degree have one optimum each (at [H2O]/[AOT] = 11 and 17 for the light and heavy subunits, respectively). When mixing micellar solutions containing both subunits, a third optimum was detected corresponding to the dimer [( H2O]/[AOT] = 26).
Nametkin
S N
SN
Kabanov
A V
AV
Evtushenko
G N
GN
Chernov
N N
NN
Berezov
T T
TT
D002384:Catalysis; D003102:Colloids; D004143:Dioctyl Sulfosuccinic Acid; D046911:Macromolecular Substances; D008823:Micelles; D011487:Protein Conformation; D005723:gamma-Glutamyltransferase
D003102:Colloids; D046911:Macromolecular Substances; D008823:Micelles; D004143:Dioctyl Sulfosuccinic Acid; D005723:gamma-Glutamyltransferase
Reguliatsiia nadmolekuliarnoĭ struktury i kataliticheskoĭ aktivnosti gamma-glutamiltransferazy v sistemakh obrashchennykh mitsell.