Effects of Temperature, Substrate, and Activating Cations on the Conformations of Pyruvate Kinase in Aqueous Solutions

A kinetic study of rabbit muscle pyruvate kinase

“…The experimental results indicate that the reaction mechanism is of the Random Tri Di type (Cleland, 1963a) (Mildvan & Cohn, 1965, 1966 Removal of metal ions from substrates, products and enzymes All substrates and products that were purchased as sodium salts (except NADH) were converted into the tetrapropylammonium salt by passing them through a column of Dowex 50W -X8 (tetrapropylammonium form) (Phillips et al, 1963;Kayne & Suelter, 1965). Stock solutions of these compounds were adjusted to pH7.0 by addition of 10% (w/v) tetrapropylammonium hydroxide, and were stored at -15°C.…”

Dichotomic Phylogenetic Tree of the Pyruvate Kinase Family

“…Pyruvate kinase, the first enzyme in which an absolute requirement for K ϩ has been documented (8), is an excellent model enzyme for studying the effect of monovalent cations particularly because in the rabbit muscle enzyme the activating effect of K ϩ is about 10,000-fold (9, 10), which, to our knowledge, is the highest reported thus far. In regard to the mechanism of action of K ϩ , it is known that this cation changes the ultraviolet and fluorescence spectra of pyruvate kinase (11)(12)(13) as well as its immunoelectrophoretic pattern (14). K ϩ also changes the structure of the active site (15)(16)(17)(18).…”

Pyruvate Kinase Revisited

“…Indeed, several physical studies showed that the conformation of the protein is modified by monovalent cations. Alkali metal ions change the UV, fluorescence polarization, and circular dichroism spectra of the enzyme (7)(8)(9)(10). They also alter its immunoelectrophoretic behavior (11) and the sedimentation velocity of the protein (12).…”