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MDP-1: A novel eukaryotic magnesium-dependent phosphatase
1Laboratory of Biochemistry, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-0320, USA. selengut@nih.gov
Biochemistry
|July 13, 2000
Summary
We discovered magnesium-dependent phosphatase-1 (MDP-1), a novel enzyme with acid phosphatase activity. This magnesium-dependent enzyme, purified from rabbit preparations, hydrolyzes specific phosphate substrates and shows conserved orthologs across species.
Area of Science:
- Biochemistry
- Enzymology
- Molecular Biology
Background:
- Investigating carbonic anhydrase III revealed novel acid phosphatase activities.
- Several distinct phosphatases were identified within these preparations.
Purpose of the Study:
- To purify, clone, express, and characterize a novel magnesium-dependent phosphatase.
- To elucidate the enzymatic properties and evolutionary conservation of this new enzyme.
Main Methods:
- Purification of the 18.6 kDa enzyme to homogeneity.
- Gene identification via peptide sequencing and database searching.
- Recombinant expression in E. coli and purification via affinity methods.
Main Results:
- The recombinant enzyme exhibits magnesium-dependent acid phosphatase activity.
- MDP-1 rapidly hydrolyzes p-nitrophenyl phosphate, ribose-5-phosphate, and phosphotyrosine.
- Orthologous genes are found in fungi, plants, and mammals, but show no homology to known phosphatase families.
Conclusions:
- MDP-1 represents a novel class of magnesium-dependent phosphatases.
- The enzyme's mechanism is independent of cysteine, histidine, or non-magnesium metal ions.
- MDP-1 is inhibited by vanadate and fluoride, suggesting its unique catalytic properties.