title: Degradation of inositol 1,3,4,5-tetrakisphosphates by porcine brain cytosol yields inositol 1,3,4-trisphosphate and inositol 1,4,5-trisphosphate.
abstract: Inositol 1,3,4,5-tetrakisphosphates (Ins(1,3,4,5)P4), 32P-labelled in positions 4 and 5 were prepared enzymatically, using [4-32P]-phosphatidylinositol 4-phosphate (PtdInsP) and [5-32P]phosphatidylinositol 4,5-bisphosphate (PtdInsP2) as substrates, respectively. Degradation studies of Ins(1,3,4,5)P4, using an enriched phosphatase preparation from porcine brain cytosol, led to the formation of two inositol trisphosphate isomers which were identified as inositol 1,3,4-trisphosphate (Ins(1,3,4)P3) and inositol 1,4,5-trisphosphate (Ins(1,4,5)P3). This novel degradation pathway of Ins(1,3,4,5)P4 to Ins(1,4,5)P3 provides an additional source for the generation of Ins(1,4,5)P3, involving a 3-phosphatase.
authors.affiliation: Institut für Pharmakologie, Freie Universität Berlin, F.R.G.
authors.forename: D
authors.initials: D
authors.lastname: Höer
authors.forename: A
authors.initials: A
authors.lastname: Kwiatkowski
authors.forename: C
authors.initials: C
authors.lastname: Seib
authors.forename: W
authors.initials: W
authors.lastname: Rosenthal
authors.forename: G
authors.initials: G
authors.lastname: Schultz
authors.forename: E
authors.initials: E
authors.lastname: Oberdisse
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology* / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates / Q000378:metabolism*; D007536:Isomerism; D009994:Osmolar Concentration; D013403:Sugar Phosphates / Q000378:metabolism*; D013552:Swine; D013997:Time Factors
chemical_list: D007295:Inositol Phosphates; D013403:Sugar Phosphates; C081655:inositol-1,3,4,5-tetrakisphosphate; D015544:Inositol 1,4,5-Trisphosphate