title: Reduction of L-phenylalanine in protein hydrolysates using L-phenylalanine ammonia-lyase from Rhodosporidium toruloides.
abstract: 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.
authors.affiliation: Research and Development Center for Industrial Fermentations (CINDEFI; UNLP, CONICET La Plata), School of Science, La Plata National University, 47 y 115, B1900ASH, La Plata, Argentina.
authors.forename: María Teresita
authors.initials: MT
authors.lastname: Castañeda
authors.affiliation: Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi, 753-8515, Japan.
authors.forename: Osao
authors.initials: O
authors.lastname: Adachi
authors.affiliation: Research and Development Center for Industrial Fermentations (CINDEFI; UNLP, CONICET La Plata), School of Science, La Plata National University, 47 y 115, B1900ASH, La Plata, Argentina. hours@biotec.org.ar.|Department of Chemical Engineering, National Technological University-La Plata Regional Faculty (UTN-FRLP), 60 y 124, La Plata, Argentina. hours@biotec.org.ar.
authors.forename: Roque Alberto
authors.initials: RA
authors.lastname: Hours
mesh_terms: D001487:Basidiomycota / Q000201:enzymology*; D002364:Caseins / Q000737:chemistry / Q000378:metabolism; D002934:Cinnamates / Q000378:metabolism; D019587:Dietary Supplements; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010649:Phenylalanine / Q000302:isolation & purification* / Q000378:metabolism*; D010650:Phenylalanine Ammonia-Lyase / Q000378:metabolism*; D010661:Phenylketonurias / Q000453:epidemiology; D011492:Protein Hydrolysates / Q000737:chemistry* / Q000378:metabolism*; D013696:Temperature
chemical_list: D002364:Caseins; D002934:Cinnamates; D011492:Protein Hydrolysates; C029010:cinnamic acid; D010649:Phenylalanine; C475729:casein hydrolysate; D010650:Phenylalanine Ammonia-Lyase
keywords: Casein acid hydrolysate; L-Phe removal; Phenylalanine ammonia-lyase; Phenylketonuria; Rhodosporidium toruloides