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Synthesis and Metabolism of the myo ‐Inositol Pentakisphosphates
Author(s) -
Rudolf Marco T.,
Kaiser Thorsten,
Guse Andreas H.,
Mayr Georg W.,
Schultz Carsten
Publication year - 1997
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199719970909
Subject(s) - inositol , chemistry , enantiomer , stereochemistry , chemical synthesis , inositol phosphate , metabolism , cytosol , biochemistry , receptor , in vitro , enzyme
All six isomeric myo ‐inositol pentakisphosphates (InsP 5 ), consisting of the two meso compounds myo ‐inositol 1,3,4,5,6‐pentakisphosphate [Ins(1,3,4,5,6)P 5 ] ( 18 ) and myo ‐inositol 1,2,3,4,6‐pentakisphosphate [Ins(1,2,3,4,6)P 5 ] ( 22 ) and two pairs of enantiomers myo ‐inositol 1,2,4,5,6‐pentakisphosphate [Ins(1,2,4,5,6)P 5 ] ( 15 ) myo ‐inositol 2,3,4,5,6‐pentakisphosphate [Ins(2,3,4,5,6)P 5 ] ( ent ‐ 15 ) and myo ‐inositol 1,2,3,5,6‐pentakisphosphate [Ins(1,2,3,5,6)P 5 ] ( 20 ) myo ‐inositol 1,2,3,4,5‐pentakisphosphate [Ins(1,2,3,4,5)P 5 ] ( ent ‐ 20 ), respectively, were synthesized. These compounds have been found in tissue, and although not resolved as pure enantiomers, their primary metabolism in a cytosolic extract from fetal calf thymus was therefore investigated by analytical HPLC. Four isomers were dephosphorylated to singly defined inositol tetrakisphosphates, while Ins(1,2,4,5,6)P 5 was phosphorylated to myo ‐inositol hexakisphosphate (InsP 6 ). Interestingly, Ins(2,3,4,5,6)P 5 was the only isomer which was not metabolized. These data demonstrate that chemically synthesized, enantiomerically pure inositol pentakisphosphate isomers are valuable tools for the unravelling of the metabolic pathways of InsP 5 turnover in living cells.