Fructose-1-phosphate-6-sulfate as an alternative substrate for aldolase and fructose-1,6-diphosphatase.

Fructose-1-phosphate-6-sulfate was prepared by direct sulfurylation of fructose, and selective phosphorylation of the 6-sulfuryl isomer by phosphofructokinase. The ketose derivative was used as a substrate for aldolase and fructose-1,6-diphosphatase. Kinetic studies with aldolase showed that the alternative substrate binds one third as well as fructose-1,6-P₂ yet 900 fold greater than fructose-1-P. The V_m was intermediate between the two ketose phosphates. From kinetic studies with skeletal muscle fructose-1,6-diphosphatase at pH 7.5 a K_m of 8 μM and a V_m approximately 6% that for fructose-1,6-P₂ was obtained.