Publications by authors named "Carlos Guerrero-Mendiola"
Article Synopsis
- - Eukarya pyruvate kinases differ from bacterial ones by having glutamate at position 117, affecting their dependence on potassium; those with E117 require K (K-dependent), while those with K117 do not (K-independent).
- - The study explores how specific amino acid residues influence the function of K-independent pyruvate kinases, particularly highlighting the roles of residues 117 and 120 in enzyme conformation and activity.
- - Results indicate that K-independent enzymes may use distinct mechanisms for catalysis compared to K-dependent ones, with K117 influencing the enzyme's structure and substrate interaction significantly.
In a previous phylogenetic study of the family of pyruvate kinase EC (2.7.1.
View Article and Find Full Text PDFEukarya pyruvate kinases have glutamate at position 117 (numbered according to the rabbit muscle enzyme), whereas in Bacteria have either glutamate or lysine and in Archaea have other residues. Glutamate at this position makes pyruvate kinases K+-dependent, whereas lysine confers K+-independence because the positively charged residue substitutes for the monovalent cation charge. Interestingly, pyruvate kinases from two characterized Crenarchaeota exhibit K+-independent activity, despite having serine at the equivalent position.
View Article and Find Full Text PDFIn a previous phylogenetic study of the family of pyruvate kinase, we found one cluster with Glu117 and another with Lys117. Those sequences with Glu117 have Thr113 and are K+-dependent, whereas those with Lys117 have Leu113 and are K+-independent. The carbonyl oxygen of Thr113 is one of the residues that coordinate K+ in the active site.
View Article and Find Full Text PDFIn a previous study we found that 30-40% dimethylsulfoxide induces the active conformation of rabbit muscle pyruvate kinase. Because dimethylsulfoxide is known to perturb structure and function of many proteins, we have explored the effect of trehalose on the kinetics of thermal inactivation and stability of pyruvate kinase; this is because trehalose, in contrast to dimethyl sulfoxide, is totally excluded from the hydration shell of proteins. The results show that 600 mM trehalose inhibits the activity of pyruvate kinase by about 20% at 25 degrees C, however, trehalose protects pyruvate kinase from thermal inactivation at 60 degrees C, increases the Tm(app) of unfolding by 7.
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