Purification and physical properties of arginase from Xenopus laevis.

Arginase from the liver of Xenopus laevis has been purified to homogeneity by heat treatment, acetone fractionation, and isoelectric focussing. The main component had an isoelectric point (I.E.P.) of 7.3; there is a minor component of I.E.P. 7.8. The molecular weight of the enzyme, as determined by gel filtration on Sephadex G200, is 76,000 daltons, substantially less than that of rat liver arginase studied concurrently. The molecular weight of the subunits, as determined by electrophoresis in sodium dodecyl sulfate, is 18,000 daltons, again less than that of rat liver arginase. The data indicate that Xenopus liver arginase, like rat liver arginase, is a tetramer. The molecular weight of arginase from adult Xenopus laevis corresponds to that from larval Rana esculenta.