Ca2+/calmodulin-dependent protein kinase V and I may form a family of isoforms

We reported that polyclonal antibody against Ca2+/calmodulin-dependent protein kinase V (CaM kinase V) reacted to two proteins of rat cerebrum with a molecular mass of 40 and 41 kDa. This antibody revealed the immunoreactivity with CaM kinase I expressed in E. coli (recombinant CaM kinase I), of which molecular mass was 40 kDa, whereas 41 kDa mainly with purified CaM kinase V. The immunoreactive bands of recombinant CaM kinase I and CaM kinase V did not shift by phosphorylation or dephosphorylation. These results suggest that CaM kinase V and CaM kinase I may form a family of isoforms.