Cytokinin Activity of a Group of Ureidopurine Derivatives Related to the tRNA Component, N-(Purin-6-ylcarbamoyl)threonine

1972 ◽  
Vol 50 (3) ◽  
pp. 237-243 ◽  
Author(s):  
W. H. Dyson ◽  
R. H. Hall ◽  
C. I. Hong ◽  
S. P. Dutta ◽  
G. B. Chheda
Keyword(s):  
Side Chain ◽  
Cytokinin Activity ◽  
Molecular Models ◽  
Straight Chain ◽  
Oh Groups ◽  
Alkyl Chains ◽  
Meta Position ◽  
Naturally Occurring ◽  
Intact Organism ◽  
Electronegative Group

Several ureidopurine derivatives have been tested for cytokinin activity in a soya bean callus assay system. N-(Purin-6-ylcarbamoyl)threonine (Ade-CO-Thr), a naturally occurring component of tRNA, is inactive in the assay. Analogues of Ade-CO-Thr having unmodified hydrocarbon side chains are active; optimal activity is associated with tert-butylureidopurine. In the homologous straight chain series n-butylureidopurine is the most active. Introduction of −COOH and/or −OH groups to analogues with otherwise active alkyl chains negates activity.The phenylureidopurine (PUP) derivative is barely active itself, though ortho-halogenated derivatives (o-chloro-, o-fluoro-PUP) are the most potent ureidopurines known. Biological activity decreases rapidly as the electronegative halide is moved from the ortho to the meta position, and lost entirely in the para position. Replacement of the ortho halide with a non-electronegative group (methyl) greatly reduces activity. Molecular models reveal that Ade-CO-Thr and o-chloro-PUP have nearly identical side-chain bulk. The carboxyl groups of Ade-CO-Thr and the chlorine atom of o-chloro-PUP occupy the same position relative to the electronegative carboxyl oxygen of the urea bridge. It is proposed that Ade-CO-Thr has a growth regulatory role in the intact organism, but that exogenous Ade-CO-Thr may be unable to reach the active site.

Organometallics in prostaglandin synthesis

1988 ◽  
Vol 326 (1592) ◽  
pp. 579-585 ◽  
Keyword(s):  
Conjugate Addition ◽  
Prostaglandin Synthesis ◽  
Side Chain ◽  
Prostaglandin E ◽  
Controlled Synthesis ◽  
One Pot ◽  
Naturally Occurring ◽  
Chain Unit ◽  
Alkyl Iodides

An extremely short way to prostaglandins has been opened by combining the newly devised organometallic methodologies. Convergent, one-pot creation of the prostanoid framework is achieved by organocopper conjugate addition of the S-configurated ω-side-chain unit to (R)-4-trialkylsiloxy-2-cyclopentenone followed by the organotin-aided trapping of the enolate intermediate by α-side-chain alkyl iodides. Prostaglandin E 2 can be prepared in only three steps from the chiral building units. The protected 5,6-didehydro-PGE 2 derivatives thus obtained serve as common intermediates for the synthesis of a variety of naturally occurring prostaglandins including prostacyclin. This approach is also useful for the controlled synthesis of isocarbacyclin.

scholarly journals Anti-Carcinogenic Glucosinolates in Cruciferous Vegetables and Their Antagonistic Effects on Prevention of Cancers

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2983 ◽  
Author(s):  
Prabhakaran Soundararajan ◽  
Jung Kim
Keyword(s):  
Antagonistic Activity ◽  
Antagonistic Effect ◽  
Side Chain ◽  
Cruciferous Vegetables ◽  
Related Factor ◽  
Nuclear Factor ◽  
Naturally Occurring ◽  
Therapeutic Properties ◽  
Responsive Element

Glucosinolates (GSL) are naturally occurring β-d-thioglucosides found across the cruciferous vegetables. Core structure formation and side-chain modifications lead to the synthesis of more than 200 types of GSLs in Brassicaceae. Isothiocyanates (ITCs) are chemoprotectives produced as the hydrolyzed product of GSLs by enzyme myrosinase. Benzyl isothiocyanate (BITC), phenethyl isothiocyanate (PEITC) and sulforaphane ([1-isothioyanato-4-(methyl-sulfinyl) butane], SFN) are potential ITCs with efficient therapeutic properties. Beneficial role of BITC, PEITC and SFN was widely studied against various cancers such as breast, brain, blood, bone, colon, gastric, liver, lung, oral, pancreatic, prostate and so forth. Nuclear factor-erythroid 2-related factor-2 (Nrf2) is a key transcription factor limits the tumor progression. Induction of ARE (antioxidant responsive element) and ROS (reactive oxygen species) mediated pathway by Nrf2 controls the activity of nuclear factor-kappaB (NF-κB). NF-κB has a double edged role in the immune system. NF-κB induced during inflammatory is essential for an acute immune process. Meanwhile, hyper activation of NF-κB transcription factors was witnessed in the tumor cells. Antagonistic activity of BITC, PEITC and SFN against cancer was related with the direct/indirect interaction with Nrf2 and NF-κB protein. All three ITCs able to disrupts Nrf2-Keap1 complex and translocate Nrf2 into the nucleus. BITC have the affinity to inhibit the NF-κB than SFN due to the presence of additional benzyl structure. This review will give the overview on chemo preventive of ITCs against several types of cancer cell lines. We have also discussed the molecular interaction(s) of the antagonistic effect of BITC, PEITC and SFN with Nrf2 and NF-κB to prevent cancer.

scholarly journals Mutant tryptophan aporepressors with altered specificities of corepressor recognition.

Genetics ◽  
1991 ◽  
Vol 128 (1) ◽  
pp. 29-35
Author(s):  
D N Arvidson ◽  
M Shapiro ◽  
P Youderian
Keyword(s):  
Dna Binding ◽  
Binding Pocket ◽  
Side Chain ◽  
Wild Type ◽  
Mutant Proteins ◽  
Naturally Occurring ◽  
Repressor Complex ◽  
Genes Encoding ◽  
Active Repressor

Abstract The Escherichia coli trpR gene encodes tryptophan aporepressor, which binds the corepressor ligand, L-tryptophan, to form an active repressor complex. The side chain of residue valine 58 of Trp aporepressor sits at the bottom of the corepressor (L-tryptophan) binding pocket. Mutant trpR genes encoding changes of Val58 to the other 19 naturally occurring amino acids were made. Each of the mutant proteins requires a higher intracellular concentration of tryptophan for activation of DNA binding than wild-type aporepressor. Whereas wild-type aporepressor is activated better by 5-methyltryptophan (5-MT) than by tryptophan, Ile58 and other mutant aporepressors prefer tryptophan to 5-MT as corepressor, and Ala58 and Gly58 prefer 5-MT much more strongly than wild-type aporepressor in vivo. These mutant aporepressors are the first examples of DNA-binding proteins with altered specificities of cofactor recognition.

scholarly journals Bioactive Compounds from Brassicaceae: a Beneficial Contribution in our Everyday Diet

2011 ◽  
Vol 68 (2) ◽  
Author(s):  
Renato IORI ◽  
Gina R. DE NICOLA ◽  
Manuela BAGATTA ◽  
Eleonora PAGNOTTA
Keyword(s):  
Secondary Metabolites ◽  
Dietary Intake ◽  
Bioactive Compounds ◽  
Chemical Structure ◽  
Side Chain ◽  
Variable Part ◽  
Naturally Occurring ◽  
Interesting Class

Dietary intake of Brassicaceae (Crucifers) provides not only nutrients, but also a highly interesting class of secondary metabolites beneficial to health, known as glucosinolates (GLs). These compounds possess a -D-glucopyranosyl unit connected to a O-sulfated anomeric Z-thiohydroximate function, and a side chain R which is the only variable part of the chemical structure. Up to now, more than 120 naturally-occurring GLs have been carachterized

scholarly journals Influence of Epoxidized Cardanol Functionality and Reactivity on Network Formation and Properties

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1956
Author(s):  
Emre Kinaci ◽  
Erde Can ◽  
John Scala ◽  
Giuseppe Palmese
Keyword(s):  
Network Formation ◽  
Glycidyl Ether ◽  
Renewable Resource ◽  
Diglycidyl Ether ◽  
Side Chain ◽  
Cashew Nut Shell Liquid ◽  
Meta Position ◽  
Cashew Nut ◽  
Link Density ◽  
Cashew Nut Shell

Cardanol is a renewable resource based on cashew nut shell liquid (CNSL), which consists of a phenol ring with a C15 long aliphatic side chain in the meta position with varying degrees of unsaturation. Cardanol glycidyl ether was chemically modified to form side-chain epoxidized cardanol glycidyl ether (SCECGE) with an average epoxy functionality of 2.45 per molecule and was cured with petroleum-based epoxy hardeners, 4-4′-methylenebis(cyclohexanamine) and diethylenetriamine, and a cardanol-based amine hardener. For comparison, cardanol-based diphenol diepoxy resin, NC514 (Cardolite), and a petroleum-based epoxy resin, diglycidyl ether of bisphenol-A (DGEBA) were also evaluated. Chemical and thermomechanical analyses showed that for SCECGE resins, incomplete cure of the secondary epoxides led to reduced cross-link density, reduced thermal stability, and reduced elongation at break when compared with difunctional resins containing only primary epoxides. However, because of functionality greater than two, amine-cured SCECGE produced a Tg very similar to that of NC514 and thus could be useful in formulating epoxy with renewable cardanol content.

Characteristics of Naturally Occurring and Pollutant Hydrocarbons in Marine Sediments

1973 ◽  
Vol 1973 (1) ◽  
pp. 205-213 ◽  
Author(s):  
M. Tissier
Keyword(s):  
Marine Sediments ◽  
Benthic Fauna ◽  
Chloroform Extract ◽  
Alkyl Chains ◽  
Marine Food Chain ◽  
Naturally Occurring ◽  
Sea Bed ◽  
Polycyclic Aromatic ◽  
The Difference

ABSTRACT Hydrocarbons spilled on the sea may, naturally or by sinking agent, settle on the sea bed and pollute marine muds which are the substratum of the benthic fauna and flora. They may be absorbed by these organisms which are the basis of the nutrition for a large part of the aquatic fauna. This hydrocarbon pollutants will enter by this way in the marine food chain and raise the problem of long term toxicity. Therefore it is important to measure the quantity of hydrocarbons in the marine sediments in order to know the level of pollution. We must, however, be able to make the difference between indigenous hydrocarbons and crude-oil derived hydrocarbons. Both contain, n and iso-alkanes, cyclo-alkanes and aromatics, but their quantity, the percentage of each type of compounds and the distribution of some specific molecules are often very particular. A detailed analysis of the chloroform extract of the sediment by chromatography, mass spectrometry and U. V. fluorescence can discriminate between unpolluted and polluted sediments even in the case of low level pollution. The samples which have been analysed, were collected on the French coast of the English channel in Normandie and in the Seine Bay. It has been noted in the unpolluted samples a higher percentage of heavy products (resins and asphaltènes), a more important odd carbon dominance in the n-alkanes distribution than in the polluted ones. The aromatic fraction of the indigenous hydrocarbons is mainly composed of polycyclic aromatic hydrocarbons without alkyl chains whereas polluted samples show many types of alkylaromatics.

Engineering oxidative stability in human hemoglobin based on the Hb providence (βK82D) mutation and genetic cross-linking

2017 ◽  
Vol 474 (24) ◽  
pp. 4171-4192 ◽  
Author(s):  
Michael Brad Strader ◽  
Rachel Bangle ◽  
Claire J. Parker Siburt ◽  
Cornelius L. Varnado ◽  
Jayashree Soman ◽  
...  
Keyword(s):  
Oxidative Degradation ◽  
Oxygen Affinity ◽  
Side Chain ◽  
Cross Linking ◽  
Critical Element ◽  
Low Oxygen ◽  
Naturally Occurring ◽  
Low Concentrations ◽  
Genetic Cross ◽  
Low Oxygen Affinity

Previous work suggested that hemoglobin (Hb) tetramer formation slows autoxidation and hemin loss and that the naturally occurring mutant, Hb Providence (HbProv; βK82D), is much more resistant to degradation by H2O2. We have examined systematically the effects of genetic cross-linking of Hb tetramers with and without the HbProv mutation on autoxidation, hemin loss, and reactions with H2O2, using native HbA and various wild-type recombinant Hbs as controls. Genetically cross-linked Hb Presbyterian (βN108K) was also examined as an example of a low oxygen affinity tetramer. Our conclusions are: (a) at low concentrations, all the cross-linked tetramers show smaller rates of autoxidation and hemin loss than HbA, which can dissociate into much less stable dimers and (b) the HbProv βK82D mutation confers more resistance to degradation by H2O2, by markedly inhibiting oxidation of the β93 cysteine side chain, particularly in cross-linked tetramers and even in the presence of the destabilizing Hb Presbyterian mutation. These results show that cross-linking and the βK82D mutation do enhance the resistance of Hb to oxidative degradation, a critical element in the design of a safe and effective oxygen therapeutic.

scholarly journals Two Novel Norwithasteroids with Unusual Six- and Seven-Membered Ether Rings in Side Chain from Flos Daturae

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Bing-You Yang ◽  
Yong-Gang Xia ◽  
Yan-Yan Wang ◽  
Qiu-Hong Wang ◽  
Hai-Xue Kuang
Keyword(s):  
Carboxylic Acid ◽  
Spectroscopic Analysis ◽  
2D Nmr ◽  
Side Chain ◽  
Macroporous Resin ◽  
Datura Metel ◽  
Naturally Occurring ◽  
The Family ◽  
Proliferation In Vitro

Chemical investigation of 50% ethanol eluate fraction of macroporous resin for the flower of Datura metel L. collected in Jiangsu province of China resulted in the isolation of two novel naturally occurring norwithasteroids, baimantuoluoline I (1) and baimantuoluoside J (2). Their structures were elucidated as 5α, 6β, 12β-trihydroxy-1-oxo-2-en-ergosta-21,24;22,29-diepoxy-26-carboxylic acid (1) and 5α, 6β, 12β, 25-tetrahydroxy-1-oxo-2-en-ergosta-21,24;22,29-diepoxy-26-carboxylic acid (2) on the basis of extensive spectroscopic analysis, including 1D, 2D-NMR, and HR-ESI-MS. According to the literatures, this study represents the first report of the norwithasteroids in the side chain with unusual six- and seven-membered ether rings instead of those with an unmodified skeleton (δ-lactone or δ-lactol side chain) and a modified skeleton (γ-lactone or γ-lactol side chain) in the family of withanolides. Meanwhile, compounds 1 and 2 were evaluated for their immunosuppressive activity against mice splenocyte proliferation in vitro.

Pteridines CV

Pteridines ◽  
1995 ◽  
Vol 6 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Tadashi Hanaya ◽  
Kiyoshi Torigoe ◽  
Kazuyuki Soranaka ◽  
Horoshi Yamamoto ◽  
Yao Qizhengt ◽  
...  
Keyword(s):  
Acetic Anhydride ◽  
Mitsunobu Reaction ◽  
Side Chain ◽  
Diethyl Acetal ◽  
Naturally Occurring ◽  
Protective Groups ◽  
Mitsunobu Reactions

Summary Treatment of L-biopterin (I) with N,N-dimethyformamide dimethyl- (or diethyl)acetal and then with acetic anhydride in pyridine gave 1',2'-di-O-acetyl-N'-(N,N-dimethylaminomethylene)-L-biopterin (4), which was converted by the Mitsunobu reaction into 3-methyl (5) and 3-p-nitrophenetyl derivatives (7). The protective groups on the side chain diols and N2 of these compounds were selectively cleaved to furnish products 6, 8-10, among which 9 is naturally occurring 3-methyl-L-biopterin and 8 is N',N(3)-protected biopterin, a versatile intermediate for various reactions on the side-chain diol. In contrast, the same Mitsunobu reactions of tri-N2:I',2'-0-acetyl-L-biopterin (II) afforded 04-methyl (12) and 04-NPE derivatives (13), both of which yielded 0 4-methyl-L-biopterin (14) and subsequently led to 4-amino-L-biopterin (18).

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