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Presence of fructokinase in pancreatic islets
Author(s) -
Malaisse Willy J.,
Malaisse-Lagae Francine,
Davies Dewi R.,
Van Schaftingen Emile
Publication year - 1989
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(89)81085-3
Subject(s) - fructokinase , fructose , phosphorylation , pancreatic islets , hexokinase , biochemistry , chemistry , kinase , fructolysis , glucokinase , islet , insulin , glycolysis , biology , enzyme , endocrinology
Homogenates of rat pancreatic islets that had been heated for 5 min at 70°C to inactive hexokinases, catalysed the ATP‐dependent phosphorylation of D‐fructose. This reaction was dependent on the presence of K + and was inhibited by D‐tagatose although not by D‐glucose or D‐glucose 6‐phosphate. The phosphorylation product was identified as fructose 1‐phosphate through its conversion to a bisphosphate ester by Clostridium difficile fructose 1‐phosphate kinase. These findings allowed the conclusion that fructokinase (ketohexokinase) was responsible for this process. Similar results were observed with tumoral insulin‐producing cells ( RIN m5F line). Fructokinase may account for a large share of fructose phosphorylation in intact islets, particularly in the presence of D‐glucose.