Phenylketonuria (PKU) is an autosomal recessive inherited disorder affecting one in every 10,000 to 15,000 newborn children in the US each year. PKU patients' metabolism of an essential amino acid, phenylalanine (PHE), is impaired, resulting in concentrations of PHE in the circulating blood and brain that are potentially toxic. Individuals with PKU restrict dietary intakes of PHE by consuming medical foods formulated with low PHE concentrations. In this study, an alkaline serine protease (ASP) expressed in Bacillus licheniformis strain 2709, which is composed of >90% protein with a concentration of <0.25% PHE, was heat deactivated (becoming deactivated ASP (DASP)) and evaluated for safe use as an ingredient in foods, including medical foods. DASP was non-mutagenic with and without metabolic activation up to 5000 μg DASP/plate. 14-Day dietary studies supported a Maximum Tolerated Dose (MTD) of 115000 ppm DASP. In a 90-day dietary toxicity study, CRL SD CD® rats were administered 0, 28750, 57500, 115500 ppm DASP in the diet. No DASP-related adverse effects were observed at high dose. As such, a No Observable Adverse Effect Level (NOAEL) of 115,500 ppm DASP or 6224.1 mg DASP/kg bw/day (males) and 7500.9 mg DASP/kg bw/day (females) was established.
Repeat-dose animal toxicity studies and genotoxicity study with deactivated alkaline serine protease (DASP), a protein low in phenylalanine (PHE).
G. Burdock,Aaron B. Cowley,Qing-Shan Li
Published 2020 in Food and Chemical Toxicology
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- Publication year
2020
- Venue
Food and Chemical Toxicology
- Publication date
2020-10-30
- Fields of study
Biology, Medicine, Chemistry
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Semantic Scholar, PubMed
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