Ribose 1,5-bisphosphate is a putative regulator of fructose 6-phosphate/fructose 1,6-bisphosphate cycle in liver.
6-Phosphofructo-1-kinase and fructose-1,6-bisphosphatase are rate-limiting enzymes for glycolysis and gluconeogenesis respectively, in the fructose 6-phosphate/fructose 1,6-bisphosphate cycle in the liver. The effect of ribose 1,5-bisphosphate on the enzymes was investigated. Ribose 1,5-bisphosphate synergistically relieved the ATP inhibition and increased the affinity of liver 6-phosphofructo-1-kinase for fructose 6-phosphate in the presence of AMP. Ribose 1,5-bisphosphate synergistically inhibited fructose-1,6-bisphosphatase in the presence of AMP. The activating effect on 6-phosphofructo-1-kinase and the inhibitory effect on fructose-1,6-bisphosphatase suggest ribose 1,5-bisphosphate is a potent regulator of the fructose 6-phosphate/fructose 1,6-bisphosphate cycle in the liver.
Sawada
M
M
Department of Physiology, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
Mitsui
Y
Y
Sugiya
H
H
Furuyama
S
S
D000818:Animals; D006597:Fructose-Bisphosphatase / Q000737:chemistry; D005635:Fructosediphosphates / Q000378:metabolism*; D005636:Fructosephosphates / Q000378:metabolism*; D008099:Liver / Q000737:chemistry / Q000378:metabolism*; D008297:Male; D010428:Pentosephosphates / Q000737:chemistry; D010732:Phosphofructokinase-1 / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley
D005635:Fructosediphosphates; D005636:Fructosephosphates; D010428:Pentosephosphates; C050562:ribose-1,5-bisphosphate; C027618:fructose-6-phosphate; D010732:Phosphofructokinase-1; D006597:Fructose-Bisphosphatase; C029063:fructose-1,6-diphosphate