Pyruvate Kinase Revisited

The conformational change of rabbit muscle pyruvate kinase induced by activating cations and its substrates

“…Trp-157 of PK is located in domain B and very close to the active site, the other two tryptophan residues (Trp-481, Trp-514) are located in domain C and close to the Y-interface. The domain C remains in the same position in the "open" and "closed" conformations [6]. Both activating cations and substrates binds to PK near to the active site, and the CD spectrum of PK also showed that there is no significant change in the secondary structure of PK in the absence or in the presence of activating cations (Fig.…”

“…K + induces the active conformation of the enzyme and proper arrangement of the residues involved in the binding of the nucleotide, allowing either PEP or ADP to bind independently (random order mechanism) [6]. The enzyme-metal complex has a conformation which is different from that of free enzyme.…”

“…The inactive state (T-state) can be represented by a rotation of the domain B in opening of the cleft between the B and A domains, and the active state (R-state) can be represented by closing of the cleft [5]. The domain B is highly mobile and differs in 40 • in the two conformers, whereas the domain C remains in the same position in the "open" and "closed" conformations [6].…”

Strategies for Improving Potassium Use Efficiency in Plants

“…Malate, glucosinolate, nitrate, glutamate, polyamine, and 2-oxoglutarate are all affected by deficiencies of various macronutrients, including K + deficiency (Amtmann and Armengaud, 2009). The activity of pyruvate kinase is very sensitive to K + availability (Guerrero-Mendiola et al, 2009; Oria-Hernandez et al, 2005; 2006; Ramirez-Silva and Oria-Hernandez, 2003; Ramirez-Silva et al, 1993; 2001). The level of phosphoenolpyruvate metabolized by pyruvate kinase is also altered by P starvation (Morcuende et al, 2007).…”

Dichotomic Phylogenetic Tree of the Pyruvate Kinase Family

“…In this respect, NMR studies of Tl ϩ bound to pyruvate kinase show that the alkali metal ion binds within 0.8 nm of the Mn 2ϩ -binding site (16) and that this distance shifts to 0.49 nm upon binding of the substrate phosphoenolpyruvate (19). In addition, it has been shown that K ϩ changes the kinetic mechanism of rabbit muscle pyruvate kinase and is involved in the acquisition of the active conformation of the enzyme (20 (21), a water molecule, and a phosphate oxygen of phosphoenolpyruvate analogs (22), or an oxygen from the ␥-phosphate of ATP (5). For a long time, it was thought that the absolute dependence of K ϩ was a common feature to all pyruvate kinases (8,(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38).…”