p-Nitrophenylphosphocholine phosphodiesterase activity was purified 5000-fold from mouse brain by treatment of membranes with Bacillus cereus phospholipase C preparation and sequential chromatographies on concanavalin A-Sepharose and CM-Sephadex columns. The phosphodiesterase (Zn(2+)-requiring) showed Km and Vmax. values of 5.5 microM and 4.2 mumol/min per mg respectively in the hydrolysis of p-nitrophenylphosphocholine, and possessed an optimum pH of 10.5 and a molecular mass of approx. 74 kDa. The purified enzyme was found to convert glycerophosphocholine into glycerol and phosphocholine, with Km and Vmax. of 48 microM and 5 mumol/min per mg respectively. In the hydrolysis of glycerophosphocholine the enzyme also exhibited a Zn2+ requirement and optimal pH at 10.5. Additionally, the p-nitrophenylphosphocholine phosphodiesterase activity was competitively inhibited by glycerophosphocholine, with a Ki value of 50 microM. These observations, together with chromatographic behaviour and heat-denaturation analyses, indicate that both p-nitrophenylphosphocholine phosphodiesterase and glycerophosphocholine cholinephosphodiesterase activities reside in the same protein.
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September 1992
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Research Article|
September 01 1992
Characterization of a Zn2+-requiring glycerophosphocholine cholinephosphodiesterase possessing p-nitrophenylphosphocholine phosphodiesterase activity
Publisher: Portland Press Ltd
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© 1992 The Biochemical Society, London
1992
Biochem J (1992) 286 (2): 435–440.
Citation
D E Sok, M R Kim; Characterization of a Zn2+-requiring glycerophosphocholine cholinephosphodiesterase possessing p-nitrophenylphosphocholine phosphodiesterase activity. Biochem J 1 September 1992; 286 (2): 435–440. doi: https://doi.org/10.1042/bj2860435
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