Effect of arginine on the incorporation of 32P into rat liver and Novikoff hepatoma cytosol proteins.

It was observed that rat liver cytosol can transfer 32P from 32PO4 to acceptor proteins. 32P-labeled proteins co-purify with a class of proteins known to accept arginine at their NH2-terminal end. When arginine-14C is added to the incubation mixture, 32P incorporation is stimulated and small molecules bearing both 32P and 14C labels can be released by treating labeled proteins with leucine aminopeptidase. Novikoff hepatoma seems to have lost the ability of phosphate fixation, even though it can incorporate arginine.