Phosphofructokinase from white muscle of the rainbow trout, Oncorhynchus mykiss: purification and properties

Purification and Properties of Phosphofructokinase from Dictyostelium Discoideum

“…This value was close to that reported for the enzyme from A. mum, PI 7.3 [30], and trout muscle, PI 7.1 [32], and higher than that of rabbit muscle PFruK, PI 6.35 [35].…”

“…3), PI value, and amino acid composition ( Table 2). The activation energy of 29.12 kJ/mol was somewhat lower than those reported for PFruK from chicken liver, 46.04 kJ/mol (calculated from [%I) and trout muscle, 40.1 kJ/mol [32], assayed at temperature above 15°C and under non-inhibitory conditions with respect to ATP, but higher than that reported for the ATPinhibited liver enzyme, 1.5.9 kJ/mol [ S S ] . This is in agreement with the lack of ATP inhibition shown by I).…”

“…This molecular mass value is in the upper limit of those reported for other eukaryotic PFruKs. Thus it is lower than those determined for the two different subunits of yeast PFruK (108 and 105 kDa for the a and subunits, respectively [5]), similar to that of the Ascaris suum enzyme [30], and above those of the three subunit types of mammalian PFruKs (80, 85 and 87.5 kDa for the L, M and C subunits, respectively [31]) and the enzymes from trout muscle (76.5 kDa) [32], Fusciola hepatica (83 kDa) [33] and Trypanosoma brucei (49 kDa) [34]. When the slime mold PFruK was subjected to gel filtration on Superose 6B, the enzyme eluted as a single peak (Fig.…”

Influence of exercise on the distribution of enzymes in trout white muscle and kinetic properties of AMP-deaminase from free and bound fractions

“…Standard assay conditions for trout white muscle PFK were 20 mM imidazole-HCI buffer (pH 7.2), 5 mM MgSO 4 , 20 mM KCI, 0.15 mM NADH, 5 mM fructose-6-phosphate (F6P), 1 mM ATP, 0.5 U aldolase, 0.5 U triosephosphate isomerase, and 1 U glycerol-3-phosphate dehydrogenase (Su and Storey 1992). One unit of enzyme activity was defined as the amount producing 1 mol fructose-1, 6-bisphosphate per min at 22°C.…”

“…The activation of muscle metabolism appears to involve several regulatory mechanisms acting in concert; allosteric regulation, protein phosphorylation, and enzyme binding to subcellular macromolecules all contribute to the activation of different enzymes (Brooks and Storey 1988a;Storey 1991;Su andStorey 1992, 1994). The most controversial of these is reversible enzyme binding to subcellular macromolecules.…”