- Organocatalytic Decarboxylation of Amino Acids as a Route to Bio-based Amines and Amides
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Amino acids obtained by fermentation or recovered from protein waste hydrolysates represent an excellent renewable resource for the production of bio-based chemicals. In an attempt to recycle both carbon and nitrogen, we report here on a chemocatalytic, metal-free approach for decarboxylation of amino acids, thereby providing a direct access to primary amines. In the presence of a carbonyl compound the amino acid is temporarily trapped into a Schiff base, from which the elimination of CO2 may proceed more easily. After evaluating different types of aldehydes and ketones on their activity at low catalyst loadings (≤5 mol%), isophorone was identified as powerful organocatalyst under mild conditions. After optimisation many amino acids with a neutral side chain were converted in 28–99 % yield in 2-propanol at 150 °C. When the reaction is performed in DMF, the amine is susceptible to N-formylation. This consecutive reaction is catalysed by the acidity of the amino acid reactant itself. In this way, many amino acids were efficiently transformed to the corresponding formamides in a one-pot catalytic system.
- Claes, Laurens,Janssen, Michiel,De Vos, Dirk E.
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p. 4297 - 4306
(2019/08/26)
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- ACTIVITY-ENHANCING SUPPLEMENT
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An activity-enhancing supplement can include niacin and at least two ingredients selected from citrulline, agmatine, an endurance enhancer, a counteracting agent, a nitrogen-containing compound, a muscle building component, branched chain amino acid, and combinations thereof.
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- Clean production method of mercaptan compound
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The invention provides a clean production method of a mercaptan compound. There are two technological steps: Step 1, thiourea and halogenated hydrocarbon or active conjugated alkene react at 20-150 DEG C for 1-18 h, and after neutralization, S-alkylisothiourea is obtained; and Step 2, S-alkylisothiourea and aliphatic primary amine or secondary amine react at 20-180 DEG C for 1-24 h to obtain the mercaptan compound, and simultaneously, a substituted guanidino compound is coproduced. The mercaptan production technology has mild condition and high yield, hardly has discharge of ''three wastes (waste gas, waste water and industrial residue) '', and is a clean production method.
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Paragraph 0018
(2017/01/02)
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- Further insight into the inhibitory action of a LIM/double zinc-finger motif of an agmatinase-like protein
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Agmatine is a precursor for polyamine biosynthesis also associated to neurotransmitter, anticonvulsant, antineurotoxic and antidepressant actions in the brain. It results from decarboxylation of l-arginine by arginine decarboxylase and it is hydrolyzed to urea and putrescine by agmatinase. Recently, we have described a new protein which also hydrolyzes agmatine although its sequence greatly differs from all known agmatinases. This agmatinase-like protein (ALP) contains a LIM-like double Zn-finger domain close to its carboxyl terminus, whose removal results in a truncated variant with a 10-fold increased kcat, and a 3-fold decreased Km value for agmatine. Our proposal was that the LIM-domain functions as an autoinhibitory, regulatory entity for ALP. Results in this report provide additional support for the postulated inhibitory effect. The purified isolated LIM domain was shown to be competitively inhibitory to a truncated variant ALP (lacking the LIM-domain), but not to the wild-type species. The C453A variant was shown to be a Zn2 +-free enzyme with kinetic parameters similar to those of the truncated-ALP. A molecular dynamic simulation of a modeled LIM-domain 3D structure showed that, as a consequence of C453A mutation, the coordination of the zinc ion is broken and the structure of the zinc finger is melted. The inhibitory action of the LIM/double Zinc-finger motif was associated to a significant conformational change, as detected by tryptophan fluorescence studies, but was not related to changes in the association of the enzyme with the catalytically essential Mn2 +.
- Cofre, Jaime,Montes, Paola,Vallejos, Alejandro,Benítez, José,García, David,Martínez-Oyanedel, José,Carvajal, Nelson,Uribe, Elena
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- PROCESS FOR STRAIGHTENING KERATIN FIBRES WITH A HEATING MEANS AND DENATURING AGENTS
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The invention relates to a process for straightening keratin fibres, comprising: (i) a step in which a straightening composition containing at least two denaturing agents is applied to the keratin fibres, (ii) a step in which the temperature of the keratin fibres is raised, using a heating means, to a temperature of between 110 and 250° C.
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- Occurrence of agmatine pathway for putrescine synthesis in Selenomonas ruminatium
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Selenomonas ruminantium synthesizes cadaverine and putrescine from L-lysine and L-ornithine as the essential constituents of its peptidoglycan by a constitutive lysine/ornithine decarboxylase (LDC/ODC). S. ruminantium grew normally in the presence of the specific inhibitor for LDC/ODC, DL-α-difluoromethylornithine, when arginine was supplied in the medium. In this study, we discovered the presence of arginine decarboxylase (ADC), the key enzyme in agmatine pathway for putrescine synthesis, in S. ruminantium. We purified and characterized ADC and cloned its gene (adc) from S. ruminantium chromosomal DNA. ADC showed more than 60% identity with those of LDC/ODC/ADCs from Gram-positive bacteria, but no similarity to that from Gram-negative bacteria. In this study, we also cloned the aguA and aguB genes, encoding agmatine deiminase (AguA) and N-carbamoyl-putrescine amidohydrolase (AguB), both of which are involved in conversion from agmatine into putrescine. AguA and AguB were expressed in S. ruminantium. Hence, we concluded that S. ruminantium has both ornithine and agmatine pathways for the synthesis of putrescine.
- Liao, Shaofu,Poonpairoj, Phuntip,Ko, Kyong-Cheol,Takatuska, Yumiko,Yamaguchi, Yoshihiro,Abe, Naoki,Kaneko, Jun,Kamio, Yoshiyuki
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p. 445 - 455
(2008/09/18)
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- Stabilization of polynucleotide complexes
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Polynucleotide complexes are stabilized by adding a cryoprotectant compound and lyophilizing the resulting formulation. The lyophilized formulations are milled or sieved into a dry powder formulation which may be used to deliver the polynucleotide complex. Delivery of the polynucleotide to a desired cell tissue is accomplished by contacting the tissue with the powder to rehydrate it. In a preferred embodiment, a dry powder formulation is used to induce genetic modification of a patient's lung tissue.
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- Protecting-group strategies for the synthesis of N4-substituted, and N1,N8-disubstituted spermidines, exemplified by hirudonine
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Methods are described for the preparation of derivatives of the polyamines 1,4-diaminobutane (putrescine), and N′-(3-amihopropyl)-l,4-diaminobutane (spermidine) in which a particular amino group is modified with, e.g., a guanidino function. Specific amino groups in these polyamines were protected as ;V-trifluoroacetyl, and yV-4-azidobenzyloxycarbonyl derivatives, which were unmasked chemoselectively using methanolic ammonia, and dithiothreitol-triethylamine, respectively. Guanidino functions were introduced by an improved procedure in which an amino group was treated with 3,5-dimethyl-Ar-nitro-!//-pyrazole-l-carboximidamide in methanol to give a nitroguanidine derivative, from which the nitro group was removed by catalytic transfer hydrogenation. The methodology is exemplified by the development of efficient preparative routes to agmatine, and hirudonine. The integrity of the sequence of protection/deprotection leading to hirudonine was confirmed by a crystal-structure analysis of its sulfate. The effect of selected compounds on the uptake of putrescine into rat lung cells was determined, and showed that N4-(4-azidobenzyloxycarbonyl)spermidine was the best inhibitor (Ki = 3.4 μM).
- Golding, Bernard T.,Mitchinson, Andrew,Clegg, William,Eisegood, Mark R. J.,Griffin, Roger J.
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p. 349 - 356
(2007/10/03)
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- Discrimination of Spermidine Amino Functions by a New Protecting Group Strategy; Application to the Synthesis of Guanidinylated Polyamines, Including Hirudonine
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Agmatine and hirudonine, guanidine derivatives of putrescine and spermidine, respectively, are synthesised by the application of a new protecting group strategy for polyamines, which uses N-nitroguanidinyl as a precursor of guanidine functions and selectively blocks spermidine at N-1 and N-8 with trifluoroacetyl and at N-4 by 4-azidobenzyloxycarbonyl.
- Mitchinson, Andrew,Golding, Bernard T.,Griffin, Roger J.,O'Sullivan, Mary C.
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p. 2613 - 2614
(2007/10/02)
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- Acyl and carbamimidoyl alkanediamines
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Synthetically produced substantially pure biologically active compounds having the general formula STR1 wherein R1 is C1 -C20 alkyl, alkenyl, aryl, aralkyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, cycloalkenyl, alkylcycloalkenyl, or cycloalkenylalkyl; R2 is hydrogen, C1 -C10 alkyl or an amide-substituted alkyl having up to 10 carbon atoms; R3 is a cyclic, straight or branched chain hydrocarbon group having 2-12 carbon atoms, particularly --(CH2)n --, wherein n is 2-12; or R2 and R3 are linked together to form an alkylene chain; and R4 is selected from STR2 (substituted or unsubstituted carbamimidoyl), STR3 (dimethylpyrimidyl), or STR4 (carbamyl) wherein each of R5, R6, and R7 is hydrogen or the same or different C1 -C8 alkyl group. The compounds are useful as bactericides for a wide variety of bacteria, including S.pyogenes, B.subtilis, K.pneumoniae, M.avium, B.fragilis, C.perfringens and C.albicans.
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