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Metabolism of L-Tyrosine in Aspergillus Sojae 169

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Metabolism of L-Tyrosine in Aspergillus Sojae 169 NOTE Agric . Biol. Chem., 42 (1), 167•`169, 1979 spectra were recorded on a Hitachi 323 Recording Spectrophotometer and a Hitachi EPI-G3 Spectro Metabolism of L-Tyrosine in photometer, respectively. Aspergillus sojae The fraction eluted with n-hexane: ether (6:4) was dried up. The isolated substance was crystallized from a mixture of n-hexane and ether (29.4mg). The MP Katsumi YUASA, Keiko ISHIZUKA of the crystal was 150•`151•Ž and undepressed by and Toshio SAKASAI admixing with an authentic p-hydroxyphenylacetic acid. Both UV and IR spectra of it were identical with those Central Research Laboratories, Kikkoman Shoyu of an authentic p-hydroxyphenylacetic acid. Co., Ltd., Noda-shi, Chibaken, Japan The eluate obtained with n-hexane: ether (4:6) was Received March 31, 1977 evaporated to dryness. The residue was crystallized from a mixture of n-hexane and ether (12.4mg). The mp of the crystal was 154•Ž (anhydride) and unde Studies on microbial metabolic pathway of or meta pressed by admixing with an authentic homogentisic bolites of tyrosine with Aspergillus oryzae,l) a sake acid. The compound was also identified as homo yeast,2) Psudomonas sp.,3) Bacterium coli acidilactici4) gentisic acid by IR analysis. p-Hydroxyphenylpyruvic and Saccharomyces cerevisiae5) have so far been re acid was not detected by TLC under the experimental ported. However no report has yet appeared on the conditions described above (solvent system; benzene: isolation and identification of 2,3-dihydroxybenzoic dioxane: acetic acid=90:25:4, v/v, detection; Folin acid and homogentisic acid as microbial metabolites of reagent6). Homoprotocatechuic acid was not detected L-tyrosine. by TLC (detection; ferric chloride solution). The present paper describes the isolation and A few other strains of aspergilli were investigated for identification of 2,3-dihydroxybenzoic acid, homo their productivity of 2,3-dihydroxybenzoic acid and gentisic acid and p-hydroxyphenylacetic acid. It is homogentisic acid from L-tyrosine. The formation of shown that they are formed from DL-2,3-dihydroxy- the compounds was examined by TLC. The spots of phenylalanine(DL-2,3-DOPA), DL-2,5-DOPA and tyra 2,3-dihydroxybenzoic acid and homogentisic acid were mine, respectively, by the growing cells and resting colored green-grey and red-brown, respecively on a cells of A. sojae. And a new metabolic pathway is TLC plate by spraying ferric chloride solution. A. proposed for L-tyrosine in A. sojae. sojae (IAM 2665, IAM 2703,5 strains), A. oryzae (JAM The conidia of A. sojae were cultured on the Czapek 2630, IAM 2663) and A. awamori (IAM 2387) produced medium containing L-tyrosine (1 g/liter) at 30•Ž for 10 2,3-dihydroxybenzoic acid from L-tyrosine, but A. days. The culture broth was obtained by filtration and aureus (IAM 2393), A. usamii (ATCC 14431) and A. acidified to pH 2.0 with 4M hydrochloric acid. The niger (NISL 1785) did not have the productivity of the carboxylic acid fraction, which was extracted with compound. On the other hand, all the strains de ether from saturated sodium bicarbonate soluble scribed above, produced homogentisic acid from L- fraction in the usual way, was concentrated. The tyrosine. carboxylic acids were dissolved in 10ml of ether and The resting cells obtained from the Czapek media applied on a column (3•~30cm) packed with 30 g of containing L-tyrosine were incubated with the buffer silicic acid (100 mesh, Malinckrodt Chemical Works). solution (1/15 M phosphate buffer, pH 5.5) containing The column was eluted with the following solvent the following substances (50mg/100 ml); L-tyrosine, systems; n-hexane, 100ml; n-hexane: ether (9:1, v/v), DL-2,3-DOPA, DL-2,5-DOPA, DL-3,4-DOPA, p-hydro- 100ml; n-hexane: ether (8:2), 400ml; n-hexane: ether xyphenylpyruvic acid, tyramine, DL p-hydroxyphenyl- (7:3), 100ml; n-hexane: ether (6:4), 500ml; n-hexane; lactic acid and o-,m-,p-hydroxybenzoic acid. DL-2,3- ether (5:5), 100ml; n-hexane: ether (4:6), 800ml. DOPA and DL-2,5-DOPA were synthesized by the The eluate obtained with n-hexane: ether (8:2) was method of Neuberger.7) DL p-Hydroxyphenyllactic concentrated and subjected to preparative thin-layer acid was synthesized by the method of Buble et al.8) chromatography (TLC, 500nm, Kiesel Gel G, Merck). The incubation was carried out at 30•Ž for 20hr. The zone with Rf: 0.43 was scraped off and eluted with 2,3-Dihydroxybenzoic acid, homogentisic acid and p- ether. The isolated substance was crystallized from hydroxyphenylacetic acid were examined by TLC. distilled water (crystal: 6.5mg). The melting point As shown in Table I, it was found that 2 3-dihydroxy- (MP) of the crystal was 190•Ž. This value agrees well benzoic acid was formed from L-tyrosine and DL-2,3- with that of 2,3-dihydroxybenzoic acid. The MP was DOPA and that homogentisic acid was formed from determined on a Micromelting Point Apparatus L-tyrosine and DL-2,5-DOPA. p-Hydroxyphenylacetic (Yanagimoto Kogyo Co., Ltd.). The UV and IR acid was formed from L-tyrosine and tyramine. It was spectra of the crystal were identical with those of observed that p-hydroxyphenylpyruvic acid was de- authentic 2,3-dihydroxybenzoic acid. UV and IR graded to protocatechuic acid via p-hydroxybenzoic 168 K. YUASA, K. ISHIZUKA and T. SAKASAI TABLE L PRODUCTION OF 2,3-DIHYDROXYBENZOIC ACID, HOMOGENTISIC ACID AND p-HYDROXY- PHENYLACETIC ACID FROM VARIOUS SUBSTRATES BY THE RESTING CELLS OF A. sojae a) 2,3-Dihydroxybenzoic acid, b) Homogentisic acid, c) p-Hydroxyphenylacetic acid. Medium; 100ml of 1/15 M phosphate buffer (pH 5.5) FIG. 1. Proposed Metabolic Pathway of L-Tyrosine containing each substrate (50mg). in A. sojae. Culture condition of resting cell; 30•Ž, 20hr. A, L-tyrosine; B, L-2,3-dihydroxyphenylalanine; C, Resting cells were obtained from the Czapek media 2,3-dihydroxyphenylpyruvic acid; D, 2,3-dihydroxy containing L-tyrosine. benzoic acid; E, catechol; F, tyramine; G, p-hydroxy Production of compounds was examined by TLC. phenylacetic acid; H, L-2,5-dihydroxyphenylalanine; I, 2,5-dihydroxyphenylpyruvic acid; J, homogentisic acid and that DL-3 4-DOPA was degraded to homo acid protocatechuic acid, The same result was obtained by L-tyrosine metabolism. Our data suggest that L-2,5- the experiment using the growing cells of A. sojae. and L-2,3-DOPA are intermediates of L-tyrosine meta From the above findings, it seems that L-2,3-DOPA bolism in A. sojae, and that two compounds are and L-2,5-DOPA were intermediates of the L-tyrosine degraded to homogentisic acid and 2,3-dihydroxy metabolism in A. sojae. It was examined whether benzoic acid. 2,3-Dihydroxybenzoic acid was not 2,3-dihydroxybenzoic acid and homogentisic acid formed from o-, m- and p-hydroxybenzoic acids by the were formed from DL-2,3-DOPA and DL-2,5-DOPA in several other strains of aspergilli. Each of the strains growing cells or resting cells of A. sojae. o-, m- and was grown on the Czapek medium containing DL-2,3- p-Hydroxybenzoic acids were not precursors of 2,3- dihydroxybenzoic acid. The degradation of 2,3-di- DOPA (250 mg/250 ml) or DL-2,5-DOPA (250mg/ hydroxybenzoic acid into catechol has been reported by 250ml) at 30•Ž for 7 days. The formation of homo the authors.10) gentisic acid and 2,3-dihydroxybenzoic acid was According to the results obtained in this work, we examined by TLC. A. sojae (7 strains), A. oryzae (2 strains), A. awarnori, A. usamii, A. aureus and A. niger propose a metabolic pathway for L-tyrosine in A. sojae (Fig. 1). had the productivity of homogentisic acid from DL- 2,5-DOPA. A. usamii and A. niger had not the pro Acknowledgment. The authors wish to express our ductivity of 2,3-dihydroxybenzoic acid from DL-2,3- thanks to Prof. K. Yano, the University of Tokyo, for DOPA. All of the other strains tested (11 strains) his kind guidance and to Drs. T. Yokotsuka, N. had the convertion activity. Iguchi, F. Yoshida, S. Sugiyama, T. Mizunuma and L-2,5-and L-2,3-DOPA were not successfully iso K. Hayashi, Kikkoman Shoyu Co., Ltd., for their lated from the culture borth of A. sojae. However, encouragement and valuable advice. Neuberger7) reported that L-2,5-DOPA is an inter mediate in L-tyrosine metabolism of rat. SchepartzƒÆ) REFERENCES reported that L-2,5-DOPA is degraded to homo gentisic acid via 2,5-dihydroxyphenylpyruvic acid in 1) T. Uemura, Nippon Nogeikagaku Kaishi, 15,353 Metabolism of L-Tyrosine in Aspergillus sojae 169 (1939). 629 (1927). 2) J. Yamamoto, T. Ohmori and H. Yasui, Nippon 7) A. Neuberger, Biochem. J., 43,599 (1948). Nogeikagaku Kaishi, 40,152 (1966). 8) E. C. Buble and J. S. Butts, J. Am. Chem. Soc. 3) F. C. Happold, Biochem. Soc. Symposia, 5,85 73,4942 (1951). (1950). 9) B. Schepartz and S. Gurin, J. Biol. Chem., 180, 4) T. Tanaka, Bull. PRI, 43,4 (1963). 663 (1949). 5) S. Sentheshanmuganathan and S. R. Elsden, 10) K. Yuasa, K. Ishizuka, S. Kaburaki and T. Biochem. J., 73,568 (1960). Sakasai, Nippon Nogeikagaku Kaishi, 48,313 6) O. Folin and V. Ciocalteu, J. Biol. Chem., 73, (1974)..
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