Cyclic nucleotide-independent protein kinase from pea shoots

Protein kinase has been isolated from 6-day old etiolated pea shoots. Crude homogenates contain endogenous protein substrates for the kinase. Casein or phosvitin, but not histone, can serve as substrates for assay. DEAE-cellulose columns distinguish several forms of protein kinase activity. Cyclic nucleotides do not modify the activity of these protein kinases $\text{in vitro}$.