1. An inositol monophosphatase was purified to homogeneity from bovine brain. 2. The enzyme is a dimer of subunit Mr 29,000. 3. The enzyme hydrolyses both enantiomers of myo-inositol 1-phosphate and both enantiomers of myo-inositol 4-phosphate, but has no activity towards inositol bisphosphates, inositol trisphosphates or inositol 1,3,4,5-tetrakisphosphate. 4. Several non-inositol-containing monophosphates are also substrates. 5. The enzyme requires Mg2+ for activity, and Zn2+ supports activity to a small extent. 6. Other bivalent cations (including Zn2+) are inhibitors, competitive with Mg2+. 7. Phosphate, but not inositol, is an inhibitor competitive with substrate. 8. Li+ inhibits hydrolysis of inositol 1-phosphate and inositol 4-phosphate uncompetitively with different apparent Ki values (1.0 mM and 0.26 mM respectively).
The purification and properties of myo-inositol monophosphatase from bovine brain
- Views Icon Views
- Share Icon Share
N S Gee, C I Ragan, K J Watling, S Aspley, R G Jackson, G G Reid, D Gani, J K Shute; The purification and properties of myo-inositol monophosphatase from bovine brain. Biochem J 1 February 1988; 249 (3): 883–889. doi: https://doi.org/10.1042/bj2490883
Download citation file: