Detection and determination of factor C--a regulatory protein--in Streptomyces strains by antiserum and monoclonal antibody.

Rabbit antisera and monoclonal antibodies were raised against factor C, a regulatory protein of Streptomyces griseus. ELISA and immunoblotting techniques suitable to determine and characterize factor C antigen was detected in all the 23 Streptomyces strains and variants examined thus far and in one Bacillus subtilis too. Depending on the strain analysed it has a molecular mass of 34,000 or 70,000 in mycelial homogenates. Most of factor C was found excreted into the cultivation medium. The quantity of factor C antigen in different Streptomyces strains showed great variation. Amy+ strains were usually good producers of factor C while Amy- were not. This was consistent with our assumption that factor C was an inducer of reproductive phase in Streptomyces.