Abstract
Soybean proteins were subjected to phosphorylation with cyclic adenosine monophosphate-dependent protein kinase (A-kinase). As a result, acidic subunits of the 11S fraction were found to be phosphorylated by A-kinase. To estimate the effect of the phosphorylation, 11S acidic subunits were isolated and subjected to A-kinase phosphorylation. The optimal enzyme amount and Mg2+ concentration for the phosphorylation of 11S acidic subunits were determined to be 1.51/ml and 1.6mM, respectively. The rate of phosphorylation was 2mol/mol acidic subunits (MW 38, 000) under the above conditions. The protein structures of 11S acidic subunits, as determined from UV and CD spectra, were slightly affected by the enzymatic phosphorylation.
