SAFETY ASSESSMENT OF THE NEOMYCIN PHOSPHOTRANSFERASE-II (NPTII) PROTEIN

Two approaches were used to assess the safety of the NPTII protein for human consumption using purified E. coli produced NPTII protein that was shown to be chemically and functionally equivalent to the NPTII pr otein produced in genetically engineered cotton seed, potato tubers an d tomato fruit. The NPTII protein was shown, as expected, to degrade r apidly under simulated mammalian digestive conditions. An acute mouse gavage study confirmed that the NPTII protein caused no deleterious ef fects when administered by gavage at a cumulative target dosage of up to 5000 mg/kg of body weight. This dosage correlates to at least a mil lion fold safety factor relative to the average daily consumption of p otato or tomato, assuming all the potatoes or tomatoes consumed contai ned the NPTII protein. These results, along with previously published information, confirm that ingestion of genetically engineered plants e xpressing the NPTII protein poses no safety concerns.