Open AccessFructose 1,6-Bisphosphatase: The Role of Lysosomal Enzymes in the Modification of Catalytic and Structural Properties
Author(s) -
S. Pontremoli,
Edon Melloni,
F. Balestrero,
Adriano T. Franzi,
Antonio De Flora,
B.L. Horecker
Publication year - 1973
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.70.2.303
Subject(s) - fructose 1,6 bisphosphatase , subtilisin , biochemistry , enzyme , fructose , gluconeogenesis , chemistry , protein subunit , proteolytic enzymes , biology , gene
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.