Mutations responsible for 3-phosphoserine phosphatase deficiency

Eur J Hum Genet. 2004 Feb;12(2):163-6. doi: 10.1038/sj.ejhg.5201083.


We report the identification of the mutations in the only known case of L-3-phosphoserine phosphatase deficiency, a recessively inherited condition. The two mutations correspond to the replacement of the semiconserved Asp32 residue by an asparagine and of the extremely conserved Met52 by a threonine. The effects of both mutations were studied on the human recombinant enzyme, expressed in Escherichia coli. Met52Thr almost abolished the enzymatic activity, whereas the Asp32Asn mutation caused a 50% decrease in Vmax. In addition, L-serine, which inhibits the conversion of [(14)C] phosphoserine to serine when catalysed by the wild-type enzyme, had a lesser inhibitory effect on the Asp32Asn mutant, indicating a reduction in the rate of phosphoenzyme hydrolysis. These modifications in the properties of the enzyme are consistent with the modification in the kinetic properties observed in fibroblasts from the patient.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • DNA, Complementary
  • Humans
  • Kinetics
  • Molecular Sequence Data
  • Mutation*
  • Phosphoric Monoester Hydrolases / chemistry
  • Phosphoric Monoester Hydrolases / genetics*
  • Phosphoric Monoester Hydrolases / metabolism
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Sequence Homology, Amino Acid


  • DNA, Complementary
  • Recombinant Proteins
  • Phosphoric Monoester Hydrolases
  • phosphoserine phosphatase