Inhibition of Recombinant Aldose-6-Phosphate Reductase from Peach Leaves by Hexose-Phosphates, Inorganic Phosphate and Oxidants

Plant Cell Physiol. 2017 Jan 1;58(1):145-155. doi: 10.1093/pcp/pcw180.

Abstract

Glucitol, also known as sorbitol, is a major photosynthetic product in plants from the Rosaceae family. This sugar alcohol is synthesized from glucose-6-phosphate by the combined activities of aldose-6-phosphate reductase (Ald6PRase) and glucitol-6-phosphatase. In this work we show the purification and characterization of recombinant Ald6PRase from peach leaves. The recombinant enzyme was inhibited by glucose-1-phosphate, fructose-6-phosphate, fructose-1,6-bisphosphate and orthophosphate. Oxidizing agents irreversibly inhibited the enzyme and produced protein precipitation. Enzyme thiolation with oxidized glutathione protected the enzyme from insolubilization caused by diamide, while incubation with NADP+ (one of the substrates) completely prevented enzyme precipitation. Our results suggest that Ald6PRase is finely regulated to control carbon partitioning in peach leaves.

Keywords: Carbon partitioning; Glucitol; Peach; Prunus persica; Redox regulation; Sorbitol.

MeSH terms

  • Aldehyde Reductase / antagonists & inhibitors
  • Aldehyde Reductase / genetics
  • Aldehyde Reductase / metabolism*
  • Fructosediphosphates / metabolism
  • Fructosediphosphates / pharmacology
  • Fructosephosphates / metabolism
  • Fructosephosphates / pharmacology
  • Glucosephosphates / metabolism
  • Glucosephosphates / pharmacology
  • Glutathione Disulfide / metabolism
  • Hexosephosphates / metabolism
  • Hexosephosphates / pharmacology
  • Immunoblotting
  • Kinetics
  • Models, Biological
  • NADP / metabolism
  • Oxidants / metabolism
  • Oxidants / pharmacology
  • Phosphates / metabolism
  • Phosphates / pharmacology
  • Phylogeny
  • Plant Leaves / enzymology*
  • Plant Leaves / genetics
  • Plant Proteins / classification
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Prunus domestica / enzymology*
  • Prunus domestica / genetics
  • Recombinant Proteins / metabolism
  • Substrate Specificity
  • Sulfhydryl Compounds / metabolism

Substances

  • Fructosediphosphates
  • Fructosephosphates
  • Glucosephosphates
  • Hexosephosphates
  • Oxidants
  • Phosphates
  • Plant Proteins
  • Recombinant Proteins
  • Sulfhydryl Compounds
  • NADP
  • fructose-6-phosphate
  • glucose-1-phosphate
  • Aldehyde Reductase
  • fructose-1,6-diphosphate
  • Glutathione Disulfide