[Affinity modification of DNA-dependent RNA-polymerase of phage T7 with 5'-p-fluorosulfonylbenzoyladenosine].

The affinity modification of the DNA-dependent RNA-polymerase of bacteriophage T7 was carried out by using the specific irreversible inhibitor, 5'-p-fluorosulfonylbenzoyladenosine. The inhibitor was found to bind to the enzyme's active site; the kinetic constants of the modification were calculated. The stoichiometry of the covalent E.

[A thermostable protein inhibitor of protein kinase from the swine brain. Isolation of the inhibitor and interaction with the enzyme].

A heat-stable protein inhibitor of cAMP-dependent protein kinase has been isolated from pig brain tissue. During gel filtration the protein is eluted in three peaks corresponding to the tetramer, dimer and monomer. The monomer fraction was purified 609-fold.

[Mechanism of activation of cAMP-dependent protein kinase. Covalent modification of the holoenzyme by cupric 1,10-phenanthroline].

Modification of the cAMP-dependent protein kinase holoenzyme from porcine brain by cupric-1,10-phenanthroline was studied. The formation of conjugates with Mr of 180,000 and 100,000 Da, whose stoichiometry coincides with that of holoenzymes R2C2 and RC, and of a conjugate with Mr of 85,000 Da corresponding to the catalytic subunit conjugate with the proteolytic fragment of the regulatory subunit (Mr = 39,000 Da) was demonstrated. The modified enzyme was activated by cAMP.

[Mechanism of cAMP-dependent protein kinase activation. Covalent modification of the holoenzyme by dimethylsuberimidate].

Modification of the holoenzyme of cAMP-dependent protein kinase from porcine brain by dimethylsuberimidate was studied. It was demonstrated that a protein conjugate with a molecular mass of 180,000 Da and a stoichiometric formula of R2C2 evolves as a result of intermolecular cross-link formation in the holoenzyme molecule. The regulatory subunit partly protects the catalytic subunit from the inhibition by dimethylsuberimidate.