The quaternary structure and activity of newly purified XXXX synthetase from the Harderian gland of @entity840 .

@entity844 @entity72844 @entity840 @entity72829 @entity2270 @entity1718
@entity844 synthetase was isolated from the Harderian gland of @entity840 . The @entity1718 synthesized by the purified enzyme were analyzed by mass fragmentography. The purified enzyme had an inherent capacity to utilize @entity72829 and synthesize @entity72844 . Physicochemical studies indicated that an active enzyme was a dimer, consisted of two subunits of Mr = 2.5 X 10(5). The negatively stained enzyme had an electron micrographic image of an ellipsoidal contour with a continuous middle cleft along the major @entity2270 . The major and minor axes were approximately equal to 220 and 150 A, respectively. In a dimer, the subunit had a rod-like structure about 220 A long and 50 A wide. The enzyme was inactivated and dissociated into subunits by incubation at 0 degree C. The inactivated enzyme was fully reactivated by raising the temperature of the solution. The relationship between the quaternary structure of the enzyme and the occurrence of enzymatic activity was studied by high-performance liquid chromatography. Neither active monomers nor inactive dimers were found in inactivation and reactivation processes. The initial velocity of reactivation was proportional to the enzyme concentration over a concentration range of 160-800 micrograms/ml, indicating that the rate-determining step in the reactivation reaction was unimolecular.
