Assay for F-2,6-P2. 0.05 ml assay mixture [2] containing fructose-6-phosphate, NADH, PP-PFK-1, aldolase, glycerol-3phosphate dehydrogenase, and triose phosphate isomerase were pipetted into the wells containing 0.02 ml sample or F-2,6-P2 standard solution. After adding 0.01 ml pyrophosphate solution, 0.05 ml of the mixture from each of the 96 wells were simultaneously transferred on a 96-multicuvette. The absorbance was monitored at 340 nm at 25°C 10 times with intervals of 30 s for each of the 96 positions with the UML-C photometer. PP-PFK-1 activities were determined kinetically in each position by on-line data acquisition and linear regression analysis. The FTable 1. Precision of the ultramicroassay for F-2,6-P2