Subcellular localization and some properties of the enzymes hydrolysing inositol polyphosphates in rat liver

FEBS Letters

Joseph, Suresh K.¹  Williams, Rebecca J.¹ 

[1] Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA

关键词: Inositol trisphosphate;    Inositol lipid;    Phosphate;    Magnesium;    Calcium;   

DOI  :  10.1016/0014-5793(85)81061-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The hydrolysis of inositol [³²P]trisphosphate (IP₃) and inositol [³²P]bisphosphate (IP₂) has been examined in subcellular fractions of rat liver. IP₃ was degraded by an enzyme located in the plasma membrane which did not degrade IP₂. Cytosolic fractions were found to degrade both IP₃ and IP₃. The IP₃ phosphatase activity of liver plasma membranes displayed a neutral pH optimum, was Mg²⁺ dependent and was not inhibited by high concentrations of Li⁺. Half-maximal activity of the enzymes hydrolysing IP₃ and IP₂ was obtained with substrate concentrations in the range 1–2μM. The significance of these observations to the proposed Ca²⁺ -mobilizing role of IP₃ is discussed.

【 授权许可】

Unknown