Some Characteristics of Membrane-Associated Protein Kinase inLemna paucicostata

摘要

A protein kinase which phosphorylates histone was isolated from the endoplasmic reticulum-rich fractions ofLemna paucicostata. The enzyme could be solubilized by sonication, and its molecular weight was estimated as 220,000 by Sephacryl S-300 gel filtration. The optimum pH for enzyme activity was 9.0–9.5 and the activity was stimulated by Co2$, Mg2$and Mn2$. Substrate proteins which might be phosphorylated by this protein kinase were also detected in microsomal fractions ofLemnaplant