21675-62-7Relevant academic research and scientific papers
Kurahamide, a cyclic depsipeptide analog of dolastatin 13 from a marine cyanobacterial assemblage of Lyngbya sp.
Iwasaki, Arihiro,Sumimoto, Shinpei,Ohno, Osamu,Suda, Shoichiro,Suenaga, Kiyotake
, p. 609 - 613 (2014)
Kurahamide, a new dolastatin 13 analog, was isolated from a marine cyanobacterial assemblage, consisting mostly of Lyngbya sp. Its gross structure was elucidated by spectroscopic analysis, and the stereochemistries were assigned based on a chiral HPLC analysis of hydrolysis products. Kurahamide strongly inhibited elastase and chymotrypsin in vitro. In addition, kurahamide moderately inhibited the growth of human cancer cells, including HeLa and HL60 cells.
Biocatalytic photosynthesis with water as an electron donor
Ryu, Jungki,Nam, Dong Heon,Lee, Sahng Ha,Park, Chan Beum
, p. 12020 - 12025 (2014)
Efficient harvesting of unlimited solar energy and its conversion into valuable chemicals is one of the ultimate goals of scientists. With the ever-increasing concerns about sustainable growth and environmental issues, numerous efforts have been made to develop artificial photosynthetic process for the production of fuels and fine chemicals, thus mimicking natural photosynthesis. Despite the research progress made over the decades, the technology is still in its infancy because of the difficulties in kinetic coupling of whole photocatalytic cycles. Herein, we report a new type of artificial photosynthesis system that can avoid such problems by integrally coupling biocatalytic redox reactions with photocatalytic water splitting. We found that photocatalytic water splitting can be efficiently coupled with biocatalytic redox reactions by using tetracobalt polyoxometalate and Rh-based organometallic compound as hole and electron scavengers, respectively, for photoexcited [Ru(bpy)3]2+. Based on these results, we could successfully photosynthesize a model chiral compound (L-glutamate) using a model redox enzyme (glutamate dehydrogenase) upon in situ photoregeneration of cofactors.
Purification and characterization of L-glutaminase enzyme from camel liver: Enzymatic anticancer property
Maharem, Tahany M.,Emam, Manal A.,Said, Youssef A.
, p. 1213 - 1222 (2020)
L-Glutaminase has gained an important attention as glutamine-depleting enzyme in treatment of various cancers. Therefore, this study aimed to purify, characterize and investigate antitumor activity of L-glutaminase from camel liver mitochondria (CL-Glu), since no available information about CL-Glu from camel. CL-Glu was purified using cell fractionation, ultrafiltration, DEAE-and CM-cellulose chromatography columns. The purified CL-Glu was a monomer with a molecular weight of 70 ± 3 kDa, isoelectric point of 7.2, optimum temperature of 70 °C and it was active over a broad pH range with a pH optimum at pH 8.0. Its activity had a clear dependence on phosphate ions. The studied enzyme showed sigmoidal kinetics, indicated its allosteric behavior with Km of 36 ± 4 mM and Hill coefficient of 1.5 which suggested a positive cooperatively of active sites. The purified L-glutaminase exerted antitumor activity against different cell lines with the highest cytotoxic activity against Hepatocellular carcinoma cell line (HepG-2) with an IC50 value of 152 μg/ml. In conclusion, L-glutaminase was purified from camel liver using simple methods and its unique properties such as stability at both wide pH range and at high temperature along with its relatively low molecular weight, facilitated its usage in medical applications as antitumor drug.
Identification of the new chymotrypsin inhibitor micropeptin 996 by metabolomics-guided analysis
Strangman, Wendy K.,Stewart, Allison K.,Herring, Megan C.,Wright, Jeffrey L.C.
, p. 934 - 937 (2018)
An untargeted metabolomics approach was used to investigate a cultured strain of Microcystis aeruginosa (UTEX LB2386) known to be a prolific producer of a diverse class of cyanopeptides. Identification of a putative new compound with a molecular weight of 996 led to the purification and structure elucidation of this new member of the micropeptin class of cyanopeptides. Micropeptin 996 displayed potent inhibition of the serine protease enzyme chymotrypisin relative to structurally related members of this class.
N5-(4-HYDROXYBENZYL) GLUTAMINE, 4-HYDROXYBENZYLAMINE AND 4-HYDROXYBENZYLGLUCOSINOLATE IN SINAPIS SPECIES
Larsen, Lone Melchior,Olsen, Ole,Pedersen, Haastrup, Lars,Soerensen, Hilmer
, p. 895 - 896 (1984)
N5-(4-hydroxybenzyl) glutamine has been isolated from Sinapis alba L. and S. arvensis L.The identification is based on data obtained by HPLC, paper chromatography, high voltage electrophoresis, UV and NMR spectroscopy of the amide and its degra
A thermodynamic study of the hydrolysis of L-glutamine to (L-glutamate + ammonia) and of L-asparagine to (L-aspartate + ammonia)
Goldberg,Kishore,Kishore,Tewari
, p. 1077 - 1090 (2000)
Calorimetric enthalpies of reaction were measured for the two enzyme-catalyzed reactions, i.e., L-glutamine(aq) + H2O(l) = L-glutamate(aq) + ammonia(aq) (1) and L-asparagine(aq) + H2O(l) = L-aspartate(aq) + ammonia(aq) (2). The standard molar enthalpies for reference reactions involving specific species were computed using an equilibrium model that considered the multiplicity of ionic forms of the reactants and products. Using the thermodynamic quantities obtained for the reference reactions, the values of the apparent equilibrium constant for reactions 1 and 2 at 311.15 K and pH 7 were 250. In performing these calculations, it was assumed that there was no binding of Mg2+(aq) to any of the species involved in the reactions 1 and 2. The standard transformed Gibbs energy changes for these two reactions under physiological conditions were both -14 kJ/mole. The thermodynamic results were discussed with respect to the structural changes involved in these reactions.
A gold nanoparticle-mediated enzyme bioreactor for inhibitor screening by capillary electrophoresis
Zhao, Shulin,Ji, Xiaowen,Lin, Pingtan,Liu, Yi-Ming
, p. 88 - 93 (2011)
A facile protocol to prepare highly effective and durable in-line enzyme bioreactors inside capillary electrophoresis (CE) columns was developed. To demonstrate the methodology, l-glutamic dehydrogenase (GLDH) was selected as the model enzyme. GLDH was first immobilized onto 38-nm-diameter gold nanoparticles (GNPs), and the functionalized GNPs were then assembled on the inner wall at the inlet end of the CE capillary treated with polyethyleneimine (PEI), producing an in-line GLDH bioreactor. Compared with a GLDH bioreactor prepared by immobilizing GLDH directly on PEI-treated capillary, the GNP-mediated bioreactor showed a higher enzymatic activity and a much better stability. The in-capillary enzyme bioreactor was proven to be very useful for screening of GLDH inhibitors deploying the GLDH-catalyzed α-ketoglutaric acid reaction. The screening assay was preliminarily validated by using a known GLDH inhibitor, namely perphenazine. A Z′ factor value of 0.95 (n = 10) was obtained, indicating that the screening results were highly reliable. Screening of GLDH inhibitors present in medicinal plant extracts by the proposed method was demonstrated. The inhibition percentages were found to be 53% for Radix scutellariae, 45% for Radix codonopsis, 37% for Radix paeoniae alba, and 0% for the other 22 extracts tested at a concentration of 0.6 mg extract/ml.
The application of glutamic acid α-decarboxylase for the valorization of glutamic acid
Lammens, Tijs M.,De Biase, Daniela,Franssen, Maurice C. R.,Scott, Elinor L.,Sanders, Johan P. M.
, p. 1562 - 1567 (2009)
Glutamic acid is an important constituent of waste streams from biofuels production. It is an interesting starting material for the synthesis of nitrogen containing bulk chemicals, thereby decreasing the dependency on fossil fuels. On the pathway from glutamic acid to a range of molecules, the decarboxylation of glutamic acid to γ-aminobutyric acid (GABA) is an important reaction. This reaction, catalyzed by the enzyme glutamic acid α-decarboxylase (GAD) was studied on a gram scale. In this study, GAD was immobilized on Eupergit and in calcium alginate and its operational stability was determined in a buffer free system, using various reactor configurations. Immobilization was shown to increase the GAD stability. The conditions for the highest GABA production per gram of enzyme were determined by extrapolation of enzyme stability data. At 30 °C in a fed batch process this results in an average volumetric productivity of 35 kg m-3 hr-1. The cost of using GAD immobilized in calcium alginate was estimated as €5 per metric ton of product. Furthermore it was shown that the cofactor pyridoxal-5′-phosphate (PLP) could be regenerated by the addition of a small amount of α-ketoglutaric acid to the reactor. In conclusion the application of immobilized GAD in a fed batch reactor was shown to be a scalable process for the industrial production of GABA from glutamic acid. The Royal Society of Chemistry 2009.
Kinetic and mechanism of reactions of L-α-glutamic acid and L-Glutamine with pyridoxal
Pishchugin,Tuleberdiev
, p. 1362 - 1366 (2014)
The kinetics and mechanisms of condensation of pyridoxal with L-α-glutamic acid and L-glutamine were studied by UV spectroscopy and polarimetry. L-α-Glutamic acid reacts with pyridoxal to form a Schiff base whose subsequent hydrolysis gives rise to pyridoxamine and α-ketoglutaric acid. The reaction of Lglutamine with pyridoxal involves the Γ-NH 2 group and affords a Schiff base whose subsequent hydrolysis gives rise to pyridoxamine and L-α-glutamic acid.
Continuous enzyme-coupled assay for microbial transglutaminase activity
Oteng-Pabi, Samuel K.,Keillor, Jeffrey W.
, p. 169 - 173 (2013)
Transglutaminases (protein-glutamine:amine γ-glutamyltransferase, EC 2.3.2.13) are a family of calciumdependent enzymes that catalyze an acyl transfer between glutamine residues and a wide variety of primary amines. When a lysine residue acts as the acyl-acceptor substrate, a γ-glutamyl-ε- lysine isopeptide bond is formed. This isopeptide bond formation represents protein cross-linking, which is critical to several biological processes. Microbial transglutaminase (mTG) is a bacterial variant of the transglutaminase family, distinct by virtue of its calcium-independent catalysis of the isopeptidic bond formation. Furthermore, mTG's promiscuity in acyl-acceptor substrate preference highlights its biocatalytic potential. The acyl-donor substrate, however, is limited in its scope; the amino acid sequences flanking glutamine residues dramatically affect substrate specificity and activity. Here, we have developed and optimized a modified glutamate dehydrogenase assay with the intention of analyzing potential high-affinity peptides. This direct continuous assay presents significant advantages over the commonly used hydroxamate assay, including generality, sensitivity, and ease of manipulation. Furthermore, we identified 7M48 (WALQRPH), a high-affinity peptide that shows greater affinity with mTG (KM = 3 mM) than the commonly used Cbz-Gln-Gly (KM = 58 mM), attesting to its potential for application in biocatalysis and bioconjugation.
