This basic science study describes the purification and characterization of InsP3 3-kinase from rat brain, demonstrating its Ca2+/calmodulin sensitivity and enabling specific antibody production.
Purified enzyme and antiserum enable targeted InsP3 studies; leaves open roles in cardiovascular Ca2+ signaling.
Inositol 1,4,5-trisphosphate (InsP3) 3-kinase catalyses the ATP-dependent phosphorylation of InsP3 to inositol 1,3,4,5-tetrakisphosphate (InsP4). InsP3 3-kinase was purified from rat brain by Blue-Sepharose, phosphocellulose and calmodulin (CaM)-Sepharose affinity chromatography. The purified enzyme was stimulated by Ca2+/CaM by 3-6-fold as compared with the activity measured in the presence of EGTA. Rat brain InsP3 3-kinase activity was associated with two silver-stained bands of about equal activity which migrated with an apparent Mr of 50,000 on SDS/polyacrylamide gels. InsP3 3-kinase activity from rat brain could be immunoprecipitated by an antiserum against the SDS/PAGE-purified 50,000-Mr protein doublet. InsP3 kinase activity from bovine brain and the InsP3 5-phosphatase activity from rat brain were not immunoprecipitated. On Western blot, the human brain crude InsP3 3-kinase reacted specifically, but less strongly than the rat brain enzyme, with the antiserum.
No takes yet. Share an insight, caveat, or question.
Takazawa et al. (1990) studied this question.
Synapse has enriched 3 closely related papers on similar clinical questions. Consider them for comparative context: