Gel filtration behaviour of arginase in frog liver and kidney extracts

The molecular weight of arginase, determined by gel filtration of frog (Rana tigerina) liver and kidney extracts, varied with the protein concentration. It increased from about 25-27 KDa in dilute solutions to about 92-96 KDA in concentrated extracts. In addition, an arginase with a molecular weight of 45-49 KDA appeared at intermediate concentrations. The results suggest the probable aggregation of arginase monomers to yield the dimeric and tetrameric forms of the enzyme at high protein concentration in extracts.