Reduction of l‑phenylalanine in protein hydrolysates using l‑phenylalanine ammonia‑lyase from Rhodosporidium toruloides

• Autores: Castañeda, María Teresita; Adachi, Osao; Hours, Roque A.
• Año de publicación: 2015
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Ciencias Químicas; Phenylketonuria; Phenylalanine ammonialyase; Rhodosporidium toruloides; Casein acid hydrolysate; l-Phe removal
• Institución: Comisión de Investigaciones Científicas de la Provincia de Buenos Aires

l-Phenylalanine ammonia-lyase (PAL, EC 4.3.1.25) from Rhodosporidium toruloides was utilized to remove l-phenylalanine (l-Phe) from different commercial protein hydrolysates. A casein acid hydrolysate (CAH, l-Phe ~2.28 %) was employed as a model substrate. t-Cinnamic acid resulting from deamination of l-Phe was extracted, analyzed at λ = 290 nm, and used for PAL activity determination. Optimum reaction conditions, optimized using successive Doehlert design, were 35 mg mL-1 of CAH and 800 mU mL-1 of PAL, while temperature and pH were 42 °C and 8.7, respectively. Reaction kinetics of PAL with CAH was determined under optimized conditions. Then, removal of l-Phe from CAH was tested. Results showed that more than 92 % of initial l-Phe was eliminated. Similar results were obtained with other protein hydrolysates. These findings demonstrate that PAL is a useful biocatalyst for l-Phe removal from protein hydrolysates, which can be evaluated as potential ingredients in foodstuffs for PKU patients.