LOW-OXYGEN ATMOSPHERE INCREASES FRUCTOSE 2,6-BISPHOSPHATE IN FRESH-CUT CARROTS

This study was undertaken to determine the effect of low-O-2 atmospher e on the concentration of fructose 2,6-bisphosphate (Fru-2,6-P-2), whi ch can activate the enzyme pyrophosphate-dependent:phosphofructokinase (PPi-PFK) to catalyze the reaction from fructose 6-phosphate to fruct ose 1,6-bisphosphate (Fru-1,6-P-2). Fru-2,6-P-2 remained unchanged in carrot (Darccus carota L.) root shreds stored under air, but it increa sed 3.0- and 5.3-fold at 2% and 0.5% O-2 atmosphere, respectively, at 5C, and the increases were almost twice as great at 15C. The concentra tion of PP1 ranged from 17 to 33 nmol . g(-1) fresh weight, which is m ore than sufficient for the PPi-PFK to proceed. Thus, low-O-2 atmosphe re appeared to hasten glycolysis of carrot shreds by increasing Fru-2, 6-P-2, which activated PPi-PFK toward glycolysis.