Phosphoethanolamine/phosphocholine phosphatase explained

Phosphoethanolamine/phosphocholine phosphatase
Ec Number:	3.1.3.75

Phosphoethanolamine/phosphocholine phosphatase (EC 3.1.3.75, PHOSPHO1, 3X11A; systematic name phosphoethanolamine phosphohydrolase) is an enzyme highly expressed in mineralizing cells .^{[1] [2] [3]} This enzyme is implicated in bone and cartilage formation and catalyses the following chemical reactions:

(1) O-phosphoethanolamine + H₂O

\rightleftharpoons ethanolamine + phosphate

(2) phosphocholine + H₂O

\rightleftharpoons choline + phosphate

The enzyme is a member of the haloacid dehalogenase superfamily. Like other members of this superfamily it requires a metal ion for catalysis, which is usually Mg²⁺, it is also active in the presence of Co²⁺ or Mn²⁺ but exhibits a lower specific activity with these metal ions.

Notes and References

1. Houston B, Seawright E, Jefferies D, Hoogland E, Lester D, Whitehead C, Farquharson C . Identification and cloning of a novel phosphatase expressed at high levels in differentiating growth plate chondrocytes . Biochimica et Biophysica Acta . 1448 . 3 . 500–6 . January 1999 . 9990301 . 10.1016/s0167-4889(98)00153-0 .
2. Stewart AJ, Schmid R, Blindauer CA, Paisey SJ, Farquharson C . Comparative modelling of human PHOSPHO1 reveals a new group of phosphatases within the haloacid dehalogenase superfamily . Protein Engineering . 16 . 12 . 889–95 . December 2003 . 14983068 . 10.1093/protein/gzg126 . free .
3. Roberts SJ, Stewart AJ, Sadler PJ, Farquharson C . Human PHOSPHO1 exhibits high specific phosphoethanolamine and phosphocholine phosphatase activities . The Biochemical Journal . 382 . Pt 1 . 59–65 . August 2004 . 15175005 . 1133915 . 10.1042/bj20040511 .