An NMR Study on Keto-Enol Tautomerism of Indole-3-Pyruvic Acid

Abstract

Abstract:

Indole-3-pyruvic acid is an important α-keto acid in the tryptophan pathway. In this work, two main forms of indole-3-pyruvic acid in acetonitrile and water solutions were studied using multi-dimensional NMR techniques. The results showed that both forms were present, and the enol-form of indole-3-pyruvic acid was the dominant form in acetontrile whereas the keto-form was the main form in water. This work provided detailed assignments for the ¹H and ¹³C NMR signals from both the enol- and keto-forms of indole-3-pyruvic acid, offering essential spectroscopic information for this metabolite.

Key words: NMR, assignment, 2D NMR, indole-3-pyruvic acid

CLC Number:

O482.53

YANG Xiao-yan1,2，WU Xiang-yu1,2，AN Yan-peng1,2，TANG Hui-ru1*.

An NMR Study on Keto-Enol Tautomerism of Indole-3-Pyruvic Acid

[J]. Chinese Journal of Magnetic Resonance.

References

[1] Badenochjones J, Summons R E, Rolfe B G, et al. Phytohormones, Rhizobium mutants, and nodulation in legumes .4.auxin metabolites in pea root-nodules[J]. J Plant Growth Regul, 1984, 3(1): 23－39.

[2] Cooney T P, Nonhebel H M. The measurement and mass-spectral identification of indole-3-pyruvate from tomato shoots[J]. Biochem Biophys Res Commun, 1989, 162(2): 761－766.

[3] Cooney T P, Nonhebel H M. Biosynthesis of indole-3-acetic acid in tomato shoots: measurement, mass-spectral identification and incorporation of -2H from -2H₂O into indole-3-acetic acid, D- and L-tryptophan, indole-3-pyruvate and tryptamine[J]. Planta, 1991, 184(3): 368－376.

[4] Moore T C, Shaner C A. Synthesis of indoleacetic acid from tryptophan via indolepyruvic acid in cell-free extracts of pea seedlings[J]. Arch Biochem Biophys, 1968, 127(1): 613－621.

[5] Koga J. Structure and function of indolepyruvate decarboxylase, a key enzyme in indole-3-acetic-acid biosynthesis[J]. Biochim Biophys Acta-Protein Struct Molec Enzym, 1995, 1 249(1): 1－13.

[6] Politi V, Dalessio S, DiStazio G, et al. Recent Advances in Tryptophan Research: Tryptophan and Serotonin Pathways[M]. New York: Plenum Press Div Plenum Publishing Corp, 1996.

[7] Perkins M N, Stone T W. Actions of kynurenic acid and quinolinic acid in the rat hippocampus in vivo[J]. Exp Neurol, 1985, 88(3): 570－579.

[8] Libbert E, Brunn K, Drawert A, et al. Pathways of IAA production from tryptophan by plants and by their epiphytic bacteria: metabolism of indolepyruvic acid and indolelactic acid[J]. Biol Plant, 1970, 12(4): 246－255.

[9] Bartolini B, Corniello C, Sella A, et al. Developments in Tryptophan and Serotonin Metabolism[M]. New York: Kluwer Academic/Plenum Publ, 2003.

[10] Penrose L, Quastel J H. Metabolic studies in phenylketonuria[J]. Biochem J, 1937, 31(2): 266－274.

[11] Bougault J, Hemmerle R. Dynamic isomerism of phenylpyruvic acid[J]. C R Hebd Seances Acad Sci, 1915, 160: 100－102.

[12] Painter H A, Zilva S S. The tautomeric conversion of p-hydroxyphenylpyruvic acid[J]. Biochem J, 1947, 41(4): 520－522.

[13] Schwarz K. Separation of enol and keto tautomers of aromatic pyruvic acids by paper chromatography[J]. Arch Biochem Biophys, 1961, 92(1): 168－175.

[14] Kaper J M, Gebhard O, Veldstra H, et al. Studies on indolepyruvic acid .2. ultraviolet spectrophotometry[J]. Arch Biochem Biophys, 1963, 103(3): 475－487.

[15] Nazario G, Schwarz K. Infrared spectra of indolepyruvic acid - study of keto-enol equilibrium in different organic solvents[J]. Arch Biochem Biophys, 1968, 123(3): 457－461.

[16] Hanai K, Kuwae A, Kawai S, et al. Keto-enol tautomerism and vibrational spectra of phenylpyruvic acids[J]. J Phys Chem, 1989, 93(16): 6 013－6 016.

[17] Lee H H, Takai T, Senda H, et al. Molecular structure of methyl phenylpyruvates studied by H-1 NMR and IR spectroscopies and quantum mechanical calculations[J]. J Mol Struct, 1998, 449(1): 69－75.

[18] Yan Xing(严星), Zhang Li-min(张利民), An Yan-peng(安艳捧), et al. NMR-based metabonomic analysis for sulprostone-induced mice(硫前列酮影响小鼠代谢的NMR 研究)[J]. Chinese J Magn Reson(波谱学杂志), 2013, 30(1): 40－54.

[19] Tian Yuan(田园), Tang Hui-ru(唐惠儒). Identification and structural determination of saccharides in rat feces(大鼠粪样中几种糖类物质的结构确定)[J]. Chinese J Magn Reson(波谱学杂志), 2012, 29(3): 361－371.