Phosphoenolpyruvate carboxylase in lupin nodules and roots. Identification of the enzymatic forms.

Phosphoenolpyruvate carboxylase (PEPC) EC 4.1.1.31 was extracted from nodules and roots of 2-day-old seedlings of lupin (Lupinus luteus L.). Chromatography on DEAE-cellulose of the nodule extract gave two forms of the enzyme: PEPC I and PEPC II eluted at 0.3-0.35 M and 0.41-0.53 M Tris buffer, respectively. A third form PEPC III from lupin roots was eluted from DEAE-cellulose column at the same buffer concentration as PEPC II from nodules. PEPC I and PEPC II eluted at 0.3-0.35 M and 0.41-0.53 M Tris buffer, more active in the 6-week-old nodules binding effectively nitrogen than in the 12-week-old ones.