Mutations responsible for 3-phosphoserine phosphatase deficiency.
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Veiga-da-Cunha M, Collet JF, Prieur B, Jaeken J, Peeraer Y, Rabbijns A, Van Schaftingen E
Mutations responsible for 3-phosphoserine phosphatase deficiency.
Eur J Hum Genet. 2004 Feb;12(2):163-6.
- PubMed ID
- 14673469 [ View in PubMed]
- Abstract
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.