Reference

L-Allothreonine aldolase

L-Allothreonine aldolase. (Denki Kagaku Kogyo K. K., Japan). Jpn. Kokai Tokkyo Koho JP 58116681 A2 11 Jul 1983 Showa, 6 pp. (Japanese). (Japan). CODEN: JKXXAF. CLASS: IC: C12N009-88. ICI: C12N009-88, C12R001-07; C12N009-88, C12R001-06; C12N009-88, C12R001-05. APPLICATION: JP 81-209982 28 Dec 1981. DOCUMENT TYPE: Patent CA Section: 7 (Enzymes) L-Allothreonine aldolase (I) is produced by culturing strains of Bacillus, Arthrobacter, Pseudomonas, and Alcaligenes. Thus, Bacillus DK-315 (FERM-P 6202) was cultured aerobically at 30° for 20 h in a medium (pH 7.5) contg. peptone 0.5, yeast ext. 0.5, KH2PO4 0.1, MgSO4 0.05, L-glutamic acid 0.Several substances like 84932-40-1 may be metioned in this study.1 and L-threonine (II) 0.1%. I was extd. from the culture cells by sonication and sepd. by (NH4)2SO4 fractionation and column chromatog. on DEAE-Sephaedex A-50 and Sephadex G-200. The I soln. was concd. to 22 mL with a membrane filter. The I prepn. had a specific activity of 1.14 and 0.01 units/mg with L-allothreonine (III) and L-II, resp. It had no activity with D-II or D-III. .

Yeast Cystathionine b-Synthase Reacts with L-Allothreonine, a Non-Natural Substrate, and L-Homocysteine To Form a New Amino Acid, 3-Methyl-L-cystathionine

Yeast Cystathionine b-Synthase Reacts with L-Allothreonine, a Non-Natural Substrate, and L-Homocysteine To Form a New Amino Acid, 3-Methyl-L-cystathionine. Jhee, Kwang-Hwan; Niks, Dimitri; McPhie, Peter; Dunn, Michael F.; Miles, Edith Wilson (Laboratory of Biochemistry and Genetics National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0830, USA). Biochemistry, 41(6), 1828-1835 (English) 2002 American Chemical Society. CODEN: BICHAW. ISSN: 0006-2960. DOCUMENT TYPE: Journal CA Section: 7 (Enzymes) Our studies of the reaction mechanism of cystathionine b-synthase from yeast (Saccharomyces cerevisiae) are facilitated by the spectroscopic properties of the pyridoxal phosphate coenzyme. The enzyme catalyzes the reaction of L-serine with L-homocysteine to form L-cystathionine through a series of pyridoxal phosphate intermediates. In this work, we explore the substrate specificity of the enzyme by use of substrate analogs combined with kinetic measurements under pre-steady-state conditions and with CD and fluorescence spectroscopy under steady-state conditions. Our results show that L-allothreonine, but not L-threonine, serves as an effective substrate. L-Allothreonine reacts with the pyridoxal phosphate cofactor to form a stable 3-Me aminoacrylate intermediate that absorbs maximally at 446 nm. The rapid-scanning stopped-flow results show that the binding of L-allothreonine as the external aldimine is faster than formation of the 3-Me aminoacrylate intermediate. The 3-Me aminoacrylate intermediate reacts with L-homocysteine to form a new amino acid, 3-methyl-L-cystathionine, which was characterized by NMR spectroscopy. This new amino acid may be a useful analog of L-cystathionine.