IMMUNOLOGICAL IDENTITY OF THE 2 DIFFERENT MOLECULAR-MASS CONSTITUTIVESUBUNITS OF LIVER ARGINASE

A detailed understanding of the regulatory mechanisms of arginase in t he cell will depend on the clarification of the origin of the two diff erent molecular mass subunits and on the arrangements of them to const itute the native enzyme. Here, we show the immunological recognition o f the 39.5 and 37.0 kDa subunits of arginase by antibodies against bot h subunits. We also find that the subunit stoichiometry (39.5 kDa: 37. 0 kDa) present in purified arginase preparations as well as in fresh i solated microsomes and cytoplasm corresponds to 3:1, indicating high p revalence of a constant arrangement of the constitutive subunits of ar ginase. These findings represent evidence for a limited posttranscipti onal or posttranslational modification of only a fraction of the synth esized arginase in liver.