title: Co-accumulation of prephenate, L-arogenate, and spiro-arogenate in a mutant of Neurospora.
abstract: A mutant strain of Neurospora crassa blocked in each of the initial steps of tryptophan, tyrosine, and phenylalanine biosynthesis was previously shown to accumulate and secrete prephenate and L-arogenate (Jensen, R.A., Zamir, L.O., St. Pierre, M., Patel, N., and Pierson, D.L. (1977) J. Bacteriol. 132, 896-903). We now report the co-accumulation of yet another compound which was identified (Zamir, L.O., Tiberio, R., Jung, E., and Jensen, R.A. (1982) J. Biol. Chem. (1983) 258, 6486-6491) as the lactam derivative of L-arogenate. This structure, spiro-arogenate, undergoes a facile acid-catalyzed conversion to L-phenylalanine (as does L-arogenate). Since L-arogenate is conveniently quantitated as 5-dimethylaminonapthalene-1-sulfonyl (dansyl)-phenylalanine following acidification and dansylation, the unknown presence of spiro-arogenate may easily lead to overestimation of L-arogenate present in mixtures. Reliable quantitative assays for both L-arogenate and spiro-arogenate in mixtures were designed utilizing [3H]dansyl-chloride and exploiting the inability of the spiro-arogenate molecule to be dansylated in contrast to L-arogenate. The initial appearance of spiro-arogenate during accumulation lagged behind prephenate and L-arogenate, and spiro-arogenate accumulation leveled off after 5 days while prephenate and L-arogenate accumulations continued. It seems likely that spiro-arogenate is derived directly from L-arogenate. Prephenate, L-arogenate, and spiro-arogenate comprised about 70, 15, and 15% fractions of the total accumulation in a representative accumulation experiment designed to maximize spiro-arogenate yields. Modest variations in co-metabolite ratios were obtained under nutritional conditions where carbon source, growth temperature, duration of incubation time, and amino acid additions were experimental variables.
mesh_terms: D000596:Amino Acids / Q000494:pharmacology; D000600:Amino Acids, Dicarboxylic / Q000378:metabolism*; D002241:Carbohydrates / Q000494:pharmacology; D003509:Cyclohexanecarboxylic Acids / Q000378:metabolism*; D053138:Cyclohexenes; D003619:Dansyl Compounds; D007700:Kinetics; D009154:Mutation; D009491:Neurospora / Q000378:metabolism*; D009492:Neurospora crassa / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D011760:Pyrrolidinones / Q000378:metabolism*; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives / Q000378:metabolism*; D012765:Shikimic Acid / Q000494:pharmacology; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D000596:Amino Acids; D000600:Amino Acids, Dicarboxylic; D002241:Carbohydrates; D003509:Cyclohexanecarboxylic Acids; D053138:Cyclohexenes; D003619:Dansyl Compounds; D011760:Pyrrolidinones; D012765:Shikimic Acid; D014443:Tyrosine; C015478:pretyrosine; C038112:delta-(spiro-4-hydroxy-2,5-cyclohexadienyl)pyroglutamate; C029038:dansyl chloride; D011761:Pyrrolidonecarboxylic Acid; C005550:prephenic acid