title: Fructose 1,6-bisphosphatase: the role of lysosomal enzymes in the modification of catalytic and structural properties.
abstract: Seasonal variations in the properties of rabbit-liver fructose 1,6-bisphosphatase have now been linked to corresponding changes in the levels of proteolytic activity in the liver extracts. Incubation of native fructose 1,6-bisphosphatase with purified liver lysosomes causes a 3-fold increase in catalytic activity at pH 9.2, with a smaller, and variable, decrease in activity tested at pH 7.5. These changes in catalytic properties are accompanied by the appearance of a smaller subunit, as was previously reported for the enzyme treated with subtilisin. AMP, a negative modulator of fructose bisphosphatase activity, protects against this action of lysosomes. This proteolytic modification of fructose bisphosphatase by lysosomal enzymes may play a role in the modulation of gluconeogenesis.
mesh_terms: D000818:Animals; D002384:Catalysis; D004591:Electrophoresis, Polyacrylamide Gel; D006597:Fructose-Bisphosphatase / Q000032:analysis / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008099:Liver / Q000166:cytology / Q000201:enzymology*; D008247:Lysosomes / Q000201:enzymology*; D051379:Mice; D008862:Microsomes, Liver / Q000201:enzymology; D008930:Mitochondria, Liver / Q000201:enzymology; D008968:Molecular Conformation; D010447:Peptide Hydrolases / Q000378:metabolism / Q000502:physiology*; D010507:Periodicity; D011817:Rabbits; D012621:Seasons; D013381:Subtilisins / Q000378:metabolism / Q000494:pharmacology
chemical_list: D006597:Fructose-Bisphosphatase; D010447:Peptide Hydrolases; D013381:Subtilisins