Are sheep and buffalo prolactins sulfated?

Radioactive sulfate (35SO42-) has been shown to be incorporated into immunoprecipitable prolactin-like material from incubated minces of sheep and buffalo pituitaries. The 35S-labelled prolactin could be purified by standard procedures. On SDS-PAGE, the 35S-labelled prolactin rich fraction gives two major Coomassie blue bands around 25KDa and these on Western blot analysis gave positive bands. Radioactive [14C]-mannose was also found incorporated into the prolactin like material. The nature of sulphate link to the peptide is not known. It could be sugar-SO4 and/or Tyrosine-SO4