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|Title:||Regulation of Adenylate Kinase|
|Author(s):||Huss, Ronald John|
|Department / Program:||Biochemistry|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||While investigating concentration-dependent thermolability in crude homogenates and partially purified preparations of a temperature-sensitive adk mutant of E. coli, a protein was discovered that altered the degree of thermolability of the mutant enzyme. This protein, called an adenylate kinase-associated protein, co-purified with the wild type and mutant enzymes through several purification steps. A homogeneous preparation of the adenylate kinase-associated protein gave a single band on a sodium dodecyl sulfate-polyacrylamide gel with M(,r) = 34,000. The interaction of this protein with adenylate kinase explains why the thermolability of the mutant adenylate kinase changed during purification and the dependence of the thermolability on concentration.
Adenylate kinase isolated from a strain of E. coli that is wild type with respect to the adk locus exhibited complex kinetics characterized by substrate inhibition by AMP. Together, the effects of pH, ATP and AMP concentrations, and the adenylate kinase-associated protein had a very large influence on the activity of adenylate kinase. The largest effect on the kinetic properties of adenylate kinase was observed when the associated protein was present. The associated protein relieved substrate inhibition by AMP and increased the values of K(,m) for AMP 2.3-fold at pH 8.0 and 5.2-fold at pH 6.5. An investigation of the kinetic mechanism of adenylate kinase yielded data that were consistent with a sequential bireactant mechanism.
Studies with temperature-sensitive mutants defective in adenylate kinase have shown that changes in the activity of adenylate kinase result in coordinate changes in the concentration of adenine nucleotides, the rates of macromolecular biosynthesis, and the rate of cell growth. The effects of pH, substrate concentrations, and the adenylate kinase-associated protein on the activity of adenylate kinase have the potential for regulating macromolecular biosyntheses and cell growth.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1985.
|Date Available in IDEALS:||2014-12-15|