NASA has given permission to a pharmaceutical company to send into space aboard the next shuttle a key enzyme in the AIDS virus, a health newsletter reported Sunday.

Health Daily, a Washington medical news publication, said in its Aug. 1 issue that the Burroughs-Wellcome Co. of Research Triangle Park, N.C., is planning to fly a key enzyme from the AIDS virus aboard the shuttle Discovery, tentatively scheduled for a September launch.Discovery's main payload will be a NASA communications satellite, and the space agency has given the company permission to send the drug into space but has not given final approval.

A series of problems detected in Discovery's preparations for flight is expected to push its launch into October.

The company plans to send up the enzyme reverse transcriptase, a primary enzyme involved in the reproduction of the AIDS virus, the newsletter said. The enzyme will be a late addition to 60 other crystal growth experiments in an automated module stashed in one of the orbiter's middeck lockers.

"Shortly after achieving orbit, astronauts will mix the crystallizing agent, typically salt or alcohol in water, with proteins," Health Daily said.

Droplets of the protein solution containing the enzyme will then incubate on the end of a syringe inside a small chamber, allowing long crystals of reverse transcriptase to grow in the gravity-free environment.

Crystals grown in Burroughs-Wellcome's labs are small and of poor quality, the newsletter said, and the company hopes the enzyme crystals grown in space will be larger and reveal the three-dimensional structure of the important enzyme.

By understanding the enzyme's structure better, the company may be able to improve its drug AZT, the only drug approved as a treatment for AIDS.

AZT is believed to slow the spread the AIDS virus by interfering with reverse transcriptase. But the drug also has severe side effects, and improvements could allow AZT to interfere more efficiently with the virus.

Other experiments in the crystal growth package are aimed at improving drugs to fight arthritis, rejection of transplant organs, high blood pressure and cancer, the newsletter said.