Regulation of pyruvate kinase in hypometabolic states

Abstract

Survival in extreme environments requires drastic changes to animals' physiology and biochemistry, requiring many animals to decrease their metabolic rate. Enzymes are the mediators of metabolic functions and their regulation is critical to surviving these conditions. This thesis explores the properties of a key enzyme of glycolysis, pyruvate kinase (PK), in the freeze tolerant wood frog (Rana sylvatica), the anoxia tolerant snail (Littorina littorea) and the hibernating ground squirrel (Urocitellus richardsonii).The studies showed that temperature, allosteric effectors and other local environmental conditions play a role in regulating pyruvate kinase in response to freezing, anoxia and during hibernation. Furthermore, reversible protein phosphorylation appears to be a common regulatory mechanism of PK by reducing the activity of the enzyme in all three animals. Together, these studies show that PK is a common regulatory target of animals surviving in extreme conditions and that multiple regulatory mechanisms, especially protein phosphorylation, contribute to its regulation. iv

Direct Two-Magnon Optical Absorption inα′−NaV2O5Damascelli1, Marel2, Grüninger3 et al. 1998Phys. Rev. Lett.89101030View full textAdd to dashboardCite

“…The insulating character of α ′ -NaV 2 O 5 would be an obvious consequence of having a 1D 1/2-filled Mott-Hubbard system. Recently, this structural analysis has been questioned and the centrosymmetric space group Pmmn was proposed [7,8]. In this context, it is still possible to recover an insulating ground state assuming that the d electron, supplied by the two V ions forming a rung of the ladder, is not attached to a particular V site but is shared in a V-O-V molecular bonding orbital along the rung [8].…”