title: Aromatic amino acid biosynthesis and production of related compounds from p-hydroxyphenylpyruvic acid by rumen bacteria, protozoa and their mixture.
abstract: Aromatic amino acid biosynthesis and production of related compounds from p-hydroxyphenylpyruvic acid (HPY) by mixed rumen bacteria (B), protozoa (P), and their mixture (BP) in an in vitro system were quantitatively investigated. Microbial suspensions prepared from mature, fistulated goats fed Lucerne ( Medicago sativa) cubes and a concentrate mixture were anaerobically incubated at 39 degrees C for 12 h. Tyrosine (Tyr), phenylalanine (Phe), tryptophan (Trp) and other related compounds in both supernatants and hydrolyzates of all incubations were analyzed by HPLC. Large amounts of Tyr (27.0, 47.0 and 50.8% of disappeared HPY in B, P and BP, respectively) were produced from 1 mM HPY during a 12-h incubation period. The formation of Tyr in P was 1.8 and 1.6 times higher than those in B and BP, respectively. Appreciable amounts of Phe (3-12% of the disappeared HPY) and Trp (2-10% of the disappeared HPY) were also produced from HPY in B, P, and BP. Phe synthesis in B and P was almost similar but Trp synthesis in B was 1.8 times higher than that in P. The biosynthesis of both Phe and Trp from HPY in BP was higher than those in B plus P. A large amount of p-hydroxyphenylacetic acid (about 45% of the disappeared HPY) was produced from HPY in B which was 1.9 times higher than that in P. p-Hydroxybenzoic acid produced from HPY in P was 1.6 times higher than that in B. Considerable amounts of phenylpropionic acid, phenyllactic acid, and phenylpyruvic acid (2-6% of the disappeared HPY) were produced only in B.
authors.affiliation: Laboratory of Animal Nutrition and Biochemistry, Faculty of Agriculture, Miyazaki University, Miyazaki-shi, Japan. rikhanah@bdonline.com
authors.forename: R I
authors.initials: RI
authors.lastname: Khan
authors.forename: R
authors.initials: R
authors.lastname: Onodera
authors.forename: M R
authors.initials: MR
authors.lastname: Amin
authors.forename: N
authors.initials: N
authors.lastname: Mohammed
mesh_terms: D024322:Amino Acids, Aromatic / Q000096:biosynthesis / Q000737:chemistry; D000818:Animals; D001419:Bacteria / Q000254:growth & development / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D056890:Eukaryota / Q000254:growth & development / Q000378:metabolism; D006041:Goats; D010648:Phenylacetates / Q000378:metabolism*; D010649:Phenylalanine / Q000096:biosynthesis*; D010667:Phenylpyruvic Acids / Q000378:metabolism*; D012417:Rumen / Q000382:microbiology / Q000469:parasitology; D014443:Tyrosine / Q000096:biosynthesis*
chemical_list: D024322:Amino Acids, Aromatic; D010648:Phenylacetates; D010667:Phenylpyruvic Acids; C010590:4-hydroxyphenylpyruvic acid; C008070:4-hydroxyphenylacetic acid; D014443:Tyrosine; D010649:Phenylalanine; C025136:phenylacetic acid; C031606:phenylpyruvic acid