Using highly purified recombinant human prorenin, we report the first evidence for the formation of a stable, partially active, conformational variant of the recombinant proenzyme. The enzymatically active prorenin exhibits the following characteristics: (1) the proenzyme N-terminal sequence and molecular weight are maintained; (2) the active proenzyme is capable of cleaving a novel fluorogenic peptide substrate based on the sequence of human angiotensinogen and exhibits about 30% of mature renin specific activity for the fluorogenic substrate; (3) the active proenzyme conformation binds to, and can be eluted from, a pepstatin affinity column; and (4) the activity of the active proenzyme can be inhibited by a novel peptidomimetic renin inhibitor.