1.   But Geron has discovered an enzyme, known as human telomerase, that enables cells to grow and divide an unlimited number of times.

2.   German scientists discovered an enzyme present in malaria that appears crucial to how the parasite synthesizes hormones and other substances.

3.   Wallach discovered the enzyme with help from doctoral students Nikolai Melinin, Mark Bodkin, and Andrei Koblenki.

4.   Australian researchers have discovered an enzyme which could revolutionise cancer and AIDS treatments, they announced here Tuesday.