Role and regulation of sucrose-phosphate synthase in higher plants

Steven C. Huber, Joan L. Huber

Research output: Contribution to journalArticlepeer-review


Sucrose-phosphate synthase (SPS; E.C. is the plant enzyme thought to play a major role in sucrose biosynthesis. In photosynthetic and nonphotosynthetic tissues, SPS is regulated by metabolites and by reversible protein phosphorylation. In leaves, phosphorylation modulates SPS activity in response to light/dark signals and end-product accumulation. SPS is phosphorylated on multiple seryl residues in vivo, and the major regulatory phosphorylation site involved is Ser158 in spinach leaves and Ser162 in maize leaves. Regulation of the enzymatic activity of SPS appears to involve calcium, metabolites, and novel "coarse" control of the protein phosphatase that activates SPS. Activation of SPS also occurs during osmotic stress of leaf tissue in darkness, which may function to facilitate sucrose formation for osmoregulation. Manipulation of SPS expression in vivo confirms the role of this enzyme in the control of sucrose biosynthesis.

Original languageEnglish (US)
Pages (from-to)431-444
Number of pages14
JournalAnnual Review of Plant Physiology and Plant Molecular Biology
Issue number1
StatePublished - 1996
Externally publishedYes


  • Maize (Zea mays L.)
  • Protein kinase
  • Regulatory protein phosphorylation
  • Spinach (Spinacia oleracea L.)
  • Sucrose synthesis

ASJC Scopus subject areas

  • General Medicine


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