Metabolism of inositol(1,4,5)trisphosphate by a soluble enzyme fraction from pea (Pisum sativum) roots

Journal Article · Fri Feb 01 00:00:00 EST 1991 · Plant Physiology; (United States)

DOI:https://doi.org/10.1104/pp.95.2.412· OSTI ID:6098661

Drobak, B K; Watkins, P A.C.; Roberts, K ^[1]; Chattaway, J A ^[2]; Dawson, A P ^[3]

---

1. John Innes Inst., Norwich (England)
2. John Innes Inst., Norwich (England) Univ. of East Anglia, Norwich (England)
3. Univ. of East Anglia, Norwich (England)

Metabolism of the putative messenger molecule D-myo-inositol(1,4,5)trisphosphate (Ins(1,4,5)P{sub 3}) in plant cells has been studied using a soluble fraction from pea (pisum sativum) roots as enzyme source and (5-{sup 32}P)Ins(1,4,5)P{sub 3} and (2-{sup 3}H)Ins(1,4,5)P{sub 3} as tracers. Ins(1,4,5)P{sub 3} was rapidly converted into both lower and higher inositol phosphates. The major dephosphorylation product was inositol (4,5) bisphosphate (Ins(4,5)P{sub 2}) whereas inositol(1,4)bisphosphate (Ins(1,4)P{sub 2}) was only present in very small quantities throughout a 15 minute incubation period. In addition to these compounds, small amounts of nine other metabolites were produced including inositol and inositol(1,4,5,X)P{sub 4}. Dephosphorylation of Ins(1,4,5)P{sub 3} to Ins(4,5)P{sub 2} was dependent on Ins(1,4,5)P{sub 3} concentration and was partially inhibited by the phosphohydrolase inhibitors 2,3-diphosphoglycerate, glucose 6-phosphate, and p-nitrophenylphosphate. Conversion of Ins(1,4,5)P{sub 3} to Ins(4,5)P{sub 2} and Ins(1,4,5,X)P{sub 4} was inhibited by 55 micromolar Ca{sup 2+}. This study demonstrates that enzymes are present in plant tissues which are capable of rapidly converting Ins(1,4,5)P{sub 3} and that pathways of inositol phosphate metabolism exist which may prove to be unique to the plant kingdom.

• OSTI ID: 6098661
• Journal Information: Plant Physiology; (United States), Vol. 95:2; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
PISUM
BIOLOGICAL PATHWAYS
CALCIUM COMPOUNDS
CATIONS
ENZYME ACTIVITY
INOSITOLS
METABOLISM
METABOLITES
PHOSPHORUS 32
PLANT CELLS
ROOTS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOHYDRATES
CHARGED PARTICLES
DAYS LIVING RADIOISOTOPES
HYDROGEN COMPOUNDS
IONS
ISOTOPE APPLICATIONS
ISOTOPES
LEGUMINOSAE
LIGHT NUCLEI
MAGNOLIOPHYTA
MAGNOLIOPSIDA
MONOSACCHARIDES
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PHOSPHORUS ISOTOPES
PLANTS
RADIOISOTOPES
SACCHARIDES
551001* - Physiological Systems- Tracer Techniques