Homodimer and heterodimer forms of adult rat intestinal alkaline phosphatase.
Three forms of alkaline phosphatase have been isolated from different sections of the small intestine: F3 180 kDa from the duodenum; F2 150 kDa principally jejunal; F1 120 kDa the only ileal form. Their catalytic properties have been compared as well as the electrophoretic properties the dimer and monomer of their phosphorylated intermediates. Pi was a competitive inhibitor of F1 and F3, whereas glycerophosphate was competitive inhibitor only of F3. Pi was a non competitive inhibitor of F2 and of a mixture F1 plus F3. Heating the phosphorylated enzyme preparations led to their dissociation into the phosphorylated monomers: F1 and F3 appear to be homodimers 65 kDa and 90 kDa peptides respectively whilst F2 seems to be a dimer formed from one of each monomer. F1 was phosphorylated faster but less intensively than F3. F2 was strongly phosphorylated over a long time-course and its 65 kDa monomer fraction was phosphorylated more strongly for longer than that from F1.
Tardivel
S
S
Métabolisme minéral des Mammifères (EPHE), Physiologie, Faculté de Pharmacie, Châtenay-Malabry, France.
Razanamaniraka
L
L
Porembska
Z
Z
Crouzoulon
G
G
Fournier
P
P
Dupuis
Y
Y
D000469:Alkaline Phosphatase / Q000302:isolation & purification* / Q000378:metabolism; D000818:Animals; D004386:Duodenum / Q000201:enzymology; D007082:Ileum / Q000201:enzymology; D007421:Intestine, Small / Q000201:enzymology*; D007527:Isoenzymes / Q000302:isolation & purification* / Q000378:metabolism; D007583:Jejunum / Q000201:enzymology; D007700:Kinetics; D046911:Macromolecular Substances; D008970:Molecular Weight; D009928:Organ Specificity; D051381:Rats; D011919:Rats, Inbred Strains
D007527:Isoenzymes; D046911:Macromolecular Substances; D000469:Alkaline Phosphatase