Elsevier

FEBS Letters

Volume 333, Issues 1–2, 25 October 1993, Pages 159-164
FEBS Letters

Research letters
Sucrose-phosphate synthase phosphatase, a type 2A protein phosphatase, changes its sensitivity towards inhibition by inorganic phosphate in spinach leaves

https://doi.org/10.1016/0014-5793(93)80396-CGet rights and content
Under an Elsevier user license
open archive

Abstract

The activity of a type 2A protein phosphatase from spinach leaves was monitored using phosphorylated sucrose-phosphate synthase (SPS) as a substrate. After partial purification the overall activities of sucrose-phosphate synthase phosphatase (SPS-P) recovered from leaves harvested in the dark and in the light did not vary. However, SPS-P preparations from darkened leaves were more strongly inhibited by inorganic phosphate and certain phosphorylated compounds than preparations from illuminated or mannose fed leaves. We conclude, that activation of SPS involves an interconversion of multiple forms of SPS-P activity.

Abbreviations

SPS-P, sucrose-phosphate synthase phosphatase
Pi, inorganic phosphate
MOPS, 3-(N-morpholino)propane sulfonic acid
ATP, adenosine 5-triphosphate
CHX, cycloheximide
BSA, bovine serum albumin.

Keywords

Protein phosphatase 2A
Sucrose-phosphate synthase
Phosphate inhibition
Protein phosphorylation
Light and mannose activation

Cited by (0)