A functional arginine residue in rabbit-muscle aldolase

Rabbit muscle aldolase is irreversibly modified by the arginine-selective alpha-dicarbonyl, phenylglyoxal, loss of activity correlating with the unique modifications of one arginine residue per subunit, as determined by amino acid analysis, and (7-14C)phenylglyoxal incorporation. The affinity of the modified enzyme for dihydroxyacetone phosphate is significantly reduced while substantial protection against inactivation is afforded by fructose 1,6-disphosphate, dihydroxyacetone phosphate or phosphate ion. The nature of the substrate C-1 phosphate binding site in this enzyme is discussed in the light of these and other results.