Fructose bisphosphate aldolase from rabbit muscle. A jump in the van't Hoff plot accompanies the onset of half of the sites' reactivity.

In 40% ethylene glycol, gamma/2 = 0.11 and pH* 8.2, fructose 1,6-bisphosphate aldolase from rabbit muscle undergoes a transition: above 3 degrees C it displays 4 equivalent dihydroxyacetone phosphate binding sites, below -1 degree C the sites decrease to 2. The dissociation constant of the aldolase-dihydroxyacetone phosphate complex decreases from 10 microM at 3 degrees C to 2.65 microM at -1 degree C, its van't Hoff plot being linear between -1 degree C and -13 degrees C. The rate of the detritiation of the aldolase-(3S)-[3-3H]dihydroxyacetone phosphate complex is strongly influenced by temperature. In 40% ethylene glycol, gamma/2 = 0.01 and pH* 8.2, the apparent rate constant is 7.6 sec-1 at -5 degrees C and 0.012 sec-1 at -24 degrees C. The Arrhenius plot is linear between -5 degrees C and -24 degrees C.