- Unnatural amino acid synthesis by thermostable O-phospho-L-serine sulfhydrylase from hyperthermophilic archaeon Aeropyrum pernix K1
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O-Acetyl-L-serine sulfhydrylase (OASS) from plants and bacteria synthesizes cysteine and unnatural amino acids that are important building blocks for active pharmaceuticals and agrochemicals. A thermostable O-phospho-L-serine sulfhydrylase from hyperthermophilic archaeon Aeropyrum pernix K1 (OPSSAp) exhibits a function similar to OASS. In the present study, we examined the synthesis of various unnatural amino acids using OPSSAp and demonstrated OPSSAp could efficiently synthesize various sulfur-containing amino acids. OPSSAp would be useful for industrial production of biologically important unnatural amino acids.
- Nakamura, Takashi,Kunimoto, Kohei,Yuki, Toru,Ishikawa, Kazuhiko
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supporting information
p. 1789 - 1792
(2017/11/23)
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- Preparation method of carbocisteine
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The invention discloses a preparation method of carbocisteine. The preparation method comprises the three steps of condensation reaction, neutralization and crystallization, and recrystallization. Through adding carbonate and an antioxidant to a reaction system and strictly controlling reaction conditions, the content of impurity amino acid in a finished product is reduced substantially, and the purity and the product quality of carbocisteine are improved. The preparation method has the advantages of simplicity in operation, short production cycle, low cost, and the like.
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Paragraph 0022; 0023; 0024; 0025; 0026; 0027; 0028-0040
(2017/06/02)
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- A process for preparing carbocysteine (by machine translation)
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The invention discloses a process for preparing a compound, in particular to a process for preparing carbocysteine, which belongs to the field of organic synthetic technology; the [...] erdosteine preparation process, comprising the following steps: (a) taking L - cysteine hydrochloride monohydrate and solid chlorine acetic acid, wherein the chloroacetic acid to L - cysteine hydrochloride monohydrate quality of 60 - 70%-out, (b) the L - cysteine hydrochloride monohydrate and sodium monochloroacetate stirring to dissolve in the water, the dissolution process of the control system temperature is 15 - 25 °C, (c) of the system is adjusted to PH 7.0 - 7.5, control system temperature is 45 - 50 °C, mixing and reaction, (d) after the completion of the reaction, of the system is adjusted to PH 6.0 - 6.4, to decolorize the, absorb the impurity processing, (e) filtering, regulate filtrate of PH to 2.8 - 3.0, cooling and getting the wound and crystallization; the process route is prepared carbocysteine, has high purity, high yield, good stability, and simple process route, easy to operate and control. (by machine translation)
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Paragraph 0025; 0026
(2017/01/12)
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- Cystine Diamide Analogs for the Prevention of Cystine Stone Formation in Cystinuria
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Cystine analogs that improve the solubility of L-cystine in urine for treatment of cystinuria and which have the structure: and pharmaceutically acceptable salts, solvates and prodrugs thereof, wherein each R and R′ pair are independently selected from (i) or (ii);(i) R and R′ are independently selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alcohol, substituted or unsubstituted aryl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocyclic, and substituted or unsubstituted heteroaryl, or(ii) R and R′ together form a substituted or unsubstituted heterocyclic ring structure, or a substituted or unsubstituted heteroaryl ring structure;X is hydrogen, or an alkyl; and Y is O or S.
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Paragraph 0120-0122
(2014/07/08)
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- PURIFICATION AND PROPERTIES OF β-CYANO-L-ALANINE SYNTHASE FROM SPINACIA OLERACEA
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β-Cyano-L-alanine synthase was purified ca 6200-fold to homogeneity from the leaves of spinach (Spinacia oleracea).The purified enzyme has an apparent Mr of 60 000 and can be dissociated into identical subunits of Mr 30 000.The subunits each contain one molecule of pyridoxal 5'-phosphate.The Km value is 2.3 mM for L-cysteine and 0.73 mM for cyanide. β-Cyano-L-alanine synthase from S. oleracea also catalyses the formation of some S-substituted L-cysteines and some heterocyclic β-substituted alanines from L-cysteine or O-acetyl-L-serine.The specificity of these additional catalytic activities of the purified enzyme are compared with those of cysteine synthase purified from the same plant, and with those of β-cyano-L-alanine synthase purified from other sources.Some other properties, including the amino acid composition of the purified enzyme, are also described. - Key Word Index: Spinacia oleracea; Chenopodiaceae; spinach; β-cyano-L-alanine synthase; cysteine synthase; enzyme purification; amino acid composition; L-cysteine; O-acetyl-L-serine; β-cyano-L-alanine; heterocyclic β-substituted alanines.
- Ikegami, Fumio,Takayama, Kyoko,Tajima, Chiho,Murakoshi, Isamu
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p. 2011 - 2016
(2007/10/02)
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- ENZYMATIC SYNTHESIS OF THE NEUROEXCITATORY AMINO ACID QUISQUALIC ACID BY CYSTEINE SYNTHASE
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Key Word Index - Quisqualis indica var. villosa; Combretaceae; cysteine synthase; isoenzyme; enzyme purification; biosynthesis; heterocyclic β-substituted alanines; quisqualic acid; O-acetyl-L-serine; cysteine.Purification of cysteine synthase from the leaves of Quisqualis indica var. villosa reveals the presence of two forms of this enzyme, separated by chromatography on DEAE-Sephadex A-50.Isoenzyme A was purified 10 000-fold and had a specific activity of 10.8 U/mg protein.Isoenzyme B was purified 460-fold with a specific activity of 0.49 U/mg protein.Both isoenzymes have the same Mrs (58 000) and dissociate into identical subunits (Mr 29 000).The Km value of isoenzyme A is 1.9 mM for O-acetyl-L-serine and 59 μM for sulphide, while that of isoenzyme B is 7.1 mM for O-acetyl-L-serine and 4.0 mM for 3,5-dioxo-1,2,4-oxadiazolidine.Both isoenzymes catalyse the formation of cysteine from O-acetyl-L-serine and hydrogen sulphide, but only isoenzyme B catalyses the formation of L-quisqualic acid.Other significant differences occur in the substrate specificity of the two isoenzymes.Some properties of the purified cysteine synthase isoenzymes are also described.
- Murakoshi, Isamu,Kaneko, Masakazu,Koide, Chiharu,Ikegami, Fumio
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p. 2759 - 2764
(2007/10/02)
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- S-substituted 2-azido-3-mercapto-propionic acid ester and process for its production and use
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The subject matter of the invention are S-substituted 2-azido-3-mercapto-propionic acid esters of the general formula STR1 in which R1 is a methyl or ethyl group and R2 is an unsubstituted or substituted alkyl group, a cycloalkyl group, an unsubstituted or substituted aromatic or heteroaromatic group or a benzyl group, and a process for their production by reaction of a methyl or ethyl ester of 2-chloroacrylic acid with a corresponding thiol to form an S-substituted 2-chloro-3-mercapto-propionic acid ester and subsequently exchanging the chlorine atom with an azido group as well as use of the compounds of formula (I) as intermediate products in the production of D,L-cysteine or derivatives of D,L-cysteine.
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- Method for increasing the purity of amphoteric compound compositions
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Provided is a method of increasing the purity of amphoteric compound compositions. The method is: (a) providing an amount of a crude amphoteric compound composition, (b) using a portion of the crude composition to prepare in solution a cationic salt of the amphoteric compound, (c) using another portion of the crude composition to prepare in solution an anionic salt of the amphoteric compound, (d) mixing together the solutions wherein a precipitate is formed, and (e) collecting the precipitate which is an amphoteric compound composition of higher purity than the crude composition.
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- Optical Resolution of Racemic S-(Carboxymethyl)cysteine
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Racemic S-(carboxymethyl)cysteine obtained from racemic cysteine is resolved via its ammonium salt (R,S)-3 by preferential crystallization procedure.Furthermore, (R,S)-2 forms with optically active amines separable, diastereomeric salts.Thus, (1R,2S)-2-amino-1-phenyl-1-propanol (4) affords optically pure (R)-S-(carboxymethyl)cysteine in 93 percent yield.The resolution of (R,S)-2 is also possible with (R)-1-phenylethylamine (5).
- Kleemann, Axel,Martens, Juergen
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p. 1995 - 1998
(2007/10/02)
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- Process for the production of high purity S-carboxymethyl-L-cysteine
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Very pure S-carboxymethyl-L-cysteine is prepared by reacting L-cystine in liquid ammonia with metallic sodium to form the disodium salt of L-cysteine, evaporating the ammonia, reacting the disodium salt of L-cysteine with an aqueous solution of chloroacetic acid and precipitating the S-carboxymethyl-L-cysteine formed by acidifying the reaction mixture. There is employed 0.1 to 10 weight percent of a reducing agent based on the chloroacetic acid.
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