Purification and properties of inositol-1,4-bisphosphatase from bovine brain.
Inositol-1,4-bisphosphatase has been purified 13,000-fold from bovine brain supernatant. The enzyme is monomeric, with an apparent subunit Mr of 40,000. Maximal hydrolytic rates were observed in Tris buffer, pH 7.8, in the presence of 9 mM-Mg2+. The enzyme acted as a 1-phosphatase, hydrolysing both inositol 1,4-bisphosphate [Ins(1,4)P2] (Km 0.04 mM) and inositol 1,3,4-trisphosphate [Ins(1,3,4)P3] (Km 0.5 mM) to inositol 4-phosphate and inositol 3,4-bisphosphate respectively. Li+ inhibited the hydrolysis of both substrates in an uncompetitive manner, with apparent Ki values of 9.63 mM and 0.46 mM for Ins(1,4)P2 and Ins(1,3,4)P3 respectively.
Gee
N S
NS
Merck Sharp and Dohme Research Laboratories, Neuroscience Research Centre, Harlow, Essex, U.K.
Reid
G G
GG
Jackson
R G
RG
Barnaby
R J
RJ
Ragan
C I
CI
D000818:Animals; D001921:Brain / Q000201:enzymology*; D002417:Cattle; D002853:Chromatography, Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008094:Lithium / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology; D010744:Phosphoric Monoester Hydrolases / Q000302:isolation & purification* / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D013379:Substrate Specificity
D011189:Potassium Chloride; D008094:Lithium; D010744:Phosphoric Monoester Hydrolases; C053087:inositol-1,4-bisphosphate 1-phosphatase; D008274:Magnesium