Harvard Group Produces Insulin From Bacteria

A Harvard researcher who recently conducted experiments inducing bacteria to produce insulin--a major breakthrough in the field of recombinant DNA research--said yesterday that his research team will work toward developing techniques for isolating large quantities of the insulin.

Walter Gilbert '53, American Cancer Society Professor of Molecular Biology, said the insulin research may eventually lead to commercial production of several important proteins other than insulin--such as the human growth factor hormone--which are now available only in small quantities.

Although research teams in California last year achieved limited success in using gene-splicing techniques to induce bacteria to produce proteins, Gilbert's group was the first to induce bacteria to excrete a molecule as large as insulin.

Gilbert said that to insure the insulin would be excreted. the researchers inserted the insulin gene next to a gene for a protein the bacteria normally excreted. The insulin molecules rode "piggyback" on the excreted protein molecules across the bacterial membrane.

The insulin gene was obtained from a rat tumer. Humans, however, use rat insulin in the treatment of diabetes.

Miles to Go...

Gilbert said three major problems now face insulin research teams across the nation.

Researchers must develop techniques to separate insulin from the piggyback molecule, to produce larger quantities of insulin, and to produce human insulin rather than rat insulin, he said.

Commercial production of insulin in large quantities might hold down the price of insulin as the number of diabetics increases, and would greatly benefit diabeties who are allergic to the insulin that is now isolated from slaughtered cows and pigs. Gilbert added.

More Benefits

In addition to these benefits. Gilbert said information and techniques gained from the insulin research may pave the way for commercial production of other proteins.

"Insulin is a model system" for developing other applications of recombinant DNA research. Gilbert said.