Table 1.

Determination of the specificity of Minpp1 antibody by the presence of Minpp1 enzymatic activity in immunoprecipitates

Sample	% hydrolysis of [3H]-Ins(1,3,4,5)P4
MC3T3—control	0.0
MC3T3—IP	13.3
Rat liver—control	0.0
Rat liver—IP	38.3

Cell lysates prepared from MC3T3-E1 cells and rat liver tissues were subjected to immunoprecipitation using Minpp1 antibody as described in “Materials and methods” section. Immunoprecipitates (IP) were incubated at 37 °C for 1 h in the Minpp1 enzyme assay buffer using [³H] Ins (1,3,4,5) P₄ as substrate. A qualitative hydrolysis of the substrate was determined by analysis of radioactive products using anion exchange chromatography as described before. Qualitative data shown as average values from two experiments indicate that the Minpp1 antibody was specifically able to immunoprecipitate Minpp1 protein