Single Molecular Weight Research Articles

Single molecular weight discrete PEG compounds: emerging roles in molecular diagnostics, imaging and therapeutics

PEGylation is the process of covalently attaching polyethylene glycol (PEG) chains to various biomolecules, such as oligonucleotides, peptides, proteins and antibody fragments. The PEGylation proce...

The variable response of soil microorganisms to trace concentrations of low molecular weight organic substrates of increasing complexity

Elevated CO2 respiration rates have been observed in soils treated with complex mixtures versus single low molecular weight (LMW) organic substrates, and it has been postulated that a more diverse range of soil microorganisms responds to increasingly complex mixtures of LMW organic substrates. To test this hypothesis, 13C-labelled substrates (glycine, an amino acid mixture and an extract of water soluble compounds from plant roots) were applied at 15 μg C g−1 soil to an arable top soil. The soils were incubated and destructively sampled after 8, 24, 48, 120 and 240 h, and the 13C content of biomarker PLFA for Gram negative bacteria, Gram positive bacteria, Actinobacteria and fungi was determined. There was no significant increase in the concentration of the biomarker PLFA, apart from Actinobacteria at the end of the incubation (120 and 240 h). However there were significant changes in total PLFA concentration due to increases in the 16:0 and 18:0 PLFA, which cannot be assigned to specific functional groups of microorganisms. 13C incorporation into the biomarker PLFA of all microbial groups was significant at every time point, but more 13C was determined in the biomarker PLFA of all microbial groups after the application of the amino acid mixture compared to glycine. Calculations of the proportion of the incorporated of 13C in the different biomarker PLFA suggested the routing of substrate 13C between the microbial groups over time. This was related to the broad functional ecology (‘r’ or ‘K’ strategy) of the different microbial groups. In conclusion, we observed that the response of all microbial groups (detected as 13C incorporation) was increased by the addition of more complex mixtures of LMW organic substrates, but that different microbial groups responded differently over time.

ReInventing Pegylation with Discrete, Single Molecular Weight

ReInventing Pegylation with Discrete, Single Molecular Weight

ReInventing Pegylation with Discrete, Single Molecular Weight

RETURN TO ISSUEPREVAdvertisementNEXTReInventing Pegylation with Discrete, Single Molecular WeightCite this: Chem. Eng. News 2013, 91, 5, 19Publication Date (Print):February 3, 2013Publication History Published online31 March 2014Published inissue 3 February 2013https://doi.org/10.1021/cen-09105-ad03Copyright © 2013 Chemical & Engineering NewsArticle Views65Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (626 KB) SUBJECTS:Pegylation Get e-Alerts

Revisiting the conformation of xanthan and the effect of industrially relevant treatments

The structure and conformation of xanthan in aqueous solution following various processing treatments typically encountered in its application were investigated in this study. Treatments such as heating, autoclaving, high pressure homogenisation and irradiation were subjected to the same sample. Parameters such as weight average molecular weight (Mw), polydispersity index, root mean square radius of gyration, intrinsic viscosity and Huggins constant were used to monitor the effect of these treatments. Additionally, we have quantified the mass recovery of samples examined by gel permeation chromatography and light scattering to properly account for all fractions present in xanthan solutions. Atomic force microscopy (AFM) images together with height measurements confirmed that xanthan conformation is double helical ordered renatured state (pre-heat treated by the manufacturer) in dilute solution conditions and random coil conformation in very dilute solution. The ordered (renatured) conformation is shown to have partially molten double helix, with more flexibility than the perfectly ordered native double helix. Heat treatment for 2h at 85°C reduces the Mw of xanthan to half its initial value, and mass recovery measurements indicate that it completely overcomes its associative nature. Thermally treated xanthan solution in the dilute region leads to an order–disorder transition, as determined by contour length per unit mass. Similarly, irradiation of xanthan solution results in an order–disorder transition together with the production of single strand low molecular weight molecules. Autoclaving and high pressure homogenisation treatments cause degradation of xanthan. The results from treated xanthan solutions following high pressure homogenisation and irradiation confirm that xanthan does not reassociate. A revised summary of xanthan conformation in solution together with schematic models following the various treatments are proposed.

Chromatogram Handler: A unique computer program that efficiently processes data generated in liquid chromatographic investigations of organic ligand adsorption on mineral surfaces

We describe a unique C# computer program developed in our laboratory to efficiently manipulate data generated when a novel liquid chromatographic (LC) ‘pulsed addition’ technique is used to study organic ligand interactions with mineral surfaces. We are not aware of the existence of a program of this nature elsewhere. Geochemically-relevant ligands studied include dissolved organic matter (DOM) mixtures and single component low molecular weight organic acids. Although our LC system has three optical (absorbance and fluorescence) detection channels, the utility can process data from experiments in which data was collected in one, two or three detection channels. If not automated, data management and processing for the technique is prohibitively complex and time-consuming, due large data volumes and the number of operations involved. The input for the utility in a processing run is the set of detector output files generated during an LC experiment. During processing, the utility generates an MS Excel output file within which, for each detection channel: (i) chromatographic peak areas and peak retention times are determined, (ii) area-normalized per-injection and cumulative adsorption densities are calculated, and (iii) graphical representations of various quantities calculated from the raw data are automatically generated. When processing data from experiments with multiple detection channels, the utility additionally prepares graphs that compare recovery values calculated from data in different detection channels, and calculates (and plots) spectroscopic/chromatographic indices which are ratios of signals in various detection channels. The utility was programmed to perform these additional operations on data from multi-channel experiments because (i) ‘Interchannel’ comparisons of recovery provide insight into the differing surface behavior of distinct DOM sub-fractions, and (ii) the spectroscopic indices provide a useful new form of data that provides insight into changes in solution-phase DOM composition due to adsorptive fractionation.

An effective method to minimize the leakage current in organic thin-film transistors by using blends of various molecular weights

We report on an effective method to minimize the leakage current in an organic thin-film transistor (OTFT) by using a polymeric gate insulator, poly(vinyl phenol) (PVP). When the molecular weight (Mw) of the PVP varies, only the leakage current is affected under constant remaining electrical parameters. More importantly, through a binary mixing between two different Mw, it is found that the leakage current can be minimized. This is attributed to a reduction of the free volume in the blended PVP layer, leading to a more vigorous cross-linking reaction, as compared to a single molecular weight PVP.

Immunochemical Detection of a Vitellogenin-derived Yolk Protein in Eggs and Larvae of Asian Catfish, <i>Clarias batrachus</i>

Attempts were made in the present investigation to detect yolk proteins in the fertilized eggs (3 h post-fertilization) and larvae (4 d post-fertilization) of Clarias batrachus using western blot. Single high molecular weight protein band was detected in western blot with rabbit anti-C. batrachus vitellogenin (Vtg) serum indicating the protein to be lipovitellin (Lv). By different staining methods of this protein in electrophoresed gels, the protein was found to contain carbohydrate, lipid and phosphorous components. Thus, the yolk protein is phospholipoglycoprotein in nature. Further, in a similar western blot experiment, the yolk protein was found to be present in eggs and larvae of C. batrachus up to 6 days post-fertilization. It may be concluded that the larvae should be offered with natural or artificial feed before six days, prior to complete depletion of yolk protein for better survival.

Characterization of a novel type of HMW subunit of glutenin from Australopyrum retrofractum

The Triticeae species Australopyrum retrofractum (genome WW) produces a single high molecular weight glutenin subunit (HMW-GS) in its endosperm. However, degenerate PCR amplification of its genome DNA revealed the presence of two related HMW-GS sequences, each consisting of an open reading frame. One of these ( Glu-W1-2) has not previously been reported. Here, we sequenced Glu-W1-2 and showed that it encodes the same type of HMW-GS as Glu-W1-1, although its overall product length was much shorter, because the number of certain repetitive motifs was lower in its central region. Both A. retrofractum HMW-GSs have a unique repetitive motif, which differentiates them from other known x- and y-type subunits present in Triticeae species. We suggest that A. retrofractum must have diverged from the main Triticeae lineage prior to the Glu-1 duplication event which led to the evolution of the x- and y-type genes.

Cleaning secondary effluents with organoclays and activated carbon

AbstractBACKGROUND: Flocculation, adsorption and ultrafiltration, alone and in combination, were tested for tertiary treatment of Beer Sheva (southern Israel) municipal wastewater. The focus was on the adsorption of soluble organics with powdered activated carbon (PAC) and with organoclays.RESULTS: Adsorption on 0.6 g L−1 octadecyltrimethylammonium bromide (ODTMA) ‐ bentonite and flocculation with 130 mg L−1 FeCl3 reduced the dissolved organic carbon (DOC) level by 46%, and that was the highest DOC retention obtained with the organoclays. Retention achieved with 0.6 g L−1 PAC and 130 mg L−1 FeCl3 was 65%. Filtration through a more hydrophobic PVDF‐30 membrane for 30 min resulted in 35–40% flux drop. A reasonable 6–7% flux reduction was obtained with filtration through a more hydrophilic PS‐50 membrane.CONCLUSION: Oganoclays at low doses are a good target adsorbent for single low molecular weight molecules. On average, higher TOC retention was achieved with PAC. Introduction of adsorption as a pre‐treatment step can lead to minimization of flux losses, reduced demand for flocculation and improved economics of the entire treatment. Copyright © 2011 Society of Chemical Industry

FUNCTIONAL PEPTIDE DENDRIMERS AS MAGNETIC RESONANCE IMAGING PROBES

Novel synthetic strategies and methods have been developed for the synthesis of magnetic resonance imaging(MRI) contrasts.DTPA ligand,DOTA ligand and peptide dendrimer-based MRI probes with controllable structure were prepared.The third generation L-lysine dendrimers were synthesized by solution-phase synthesis method and convergent approach,and the primary amine groups on the surface of the dendrimers were protected by different groups.The ratio between Boc group and Cbz groups was 18 ∶ 6.The peptide dendrimers were selectively deprotected and reacted with DTPA or DOTA derivates in the presence of succinic anhydride to yield controllable ‘peripheral’functional dendrimer-based MRI contrast agents.The new compounds were confirmed by NMR,ESI-TOF MS and so on.The peptide dendrimer-based MRI probes possessing highly controlled structures and single molecular weight were tested at 1.5 T magnetic field in a clinical MRI scanner,and a 3-fold increase in T1 relaxivity to 12.53 Gd mmol.L-1.s-1 was noticed comparing to that of the clinical agent Gd-DTPA.The successful approach to synthesize the controllable dendrimer-based agent and the high T1 relaxivity of the agent opened an opportunity for the design of multifunctional dendritic contrasts for MRI.

Multifunctional gadolinium-based dendritic macromolecules as liver targeting imaging probes

The quest for highly efficient and safe contrast agents has become the key factor for successful application of magnetic resonance imaging (MRI). The gadolinium (Gd) based dendritic macromolecules, with precise and tunable nanoscopic sizes, are excellent candidates as multivalent MRI probes. In this paper, a novel series of Gd-based multifunctional peptide dendritic probes (generation 2, 3, and 4) possessing highly controlled structures and single molecular weight were designed and prepared as liver MRI probes. These macromolecular Gd-ligand agents exhibited up to 3-fold increase in T 1 relaxivity comparing to Gd-DTPA complexes. No obvious in vitro cytotoxicity was observed from the measured concentrations. These dendritic probes were further functionalized with multiple galactosyl moieties and led to much higher cell uptake in vitro as demonstrated in T 1-weighted scans. During in vivo animal studies, the probes provided better signal intensity (SI) enhancement in mouse liver, especially at 60 min post-injection, with the most efficient enhancement from the galactosyl moiety decorated third generation dendrimer. The imaging results were verified with analysis of Gd content in liver tissues. The design strategy of multifunctional Gd-ligand peptide dendritic macromolecules in this study may be used for developing other sensitive MRI probes with targeting capability.

The Effect of Sampling Methods on the Apparent Constituents of Ink from the Squid Sepioteuthis australis

Results of experiments conducted on ink recovered from the squid Sepioteuthis australis indicate that there is no epinephrine or protein naturally present in the ink as it would be ejected in vivo. Protein content was effectively zero when ink was syringed from the duct end of the ink sac of freshly killed animals. By contrast, there were proteins in samples collected from dead specimens where ink was collected by a stripping method. From these samples, a single large molecular weight protein was identified as having tyrosinase activity. Digestion of syringed ink did not yield signs of melanin-bound proteins. Analysis of supernatants after centrifugation of squid ink consistently revealed the presence of DOPA, dopamine, and taurine, whereas epinephrine and nor-epinephrine were recorded from what was believed to be contaminated ink. Histological investigations of the ink sac revealed a compartmentalised glandular structure distal to the duct end. Closer observation of the glandular tissue showed that compartments increased in size as they matured and moved further into the lumen. It was concluded that the presence of epinephrine and tyrosinase (or a related protein) in the ink of S. australis could be attributed to rupturing of basal glandular compartments or contamination from other sources during the extraction process.

Adsorption of poly-2-(dimethylamino) ethylmethacrylate-N-alkyl quaternized at the water/chloroform interface

The interfacial properties of poly-2-(dimethylamino) ethyl methacrylate-N-alkyl quaternized with octyl, decyl, dodecyl and tetradecyl bromide are studied from the chloroform to the water/chloroform interface. In order to estimate the entropy of the adsorption process, the interfacial tension was measured at several temperatures according to the Du Noüy method. The interfacial tension decrease is highly dependent on the hydrophilic–hydrophobic balance between the quaternary ammonium groups and the aliphatic side chains. The shorter the polyelectrolyte side chains the higher the interfacial activity. The excess interfacial concentrations, Γ, are determined according to the Gibbs–Szyszkowski equation and the areas covered by monomer unit at the interface σ are higher than those reported for condensed monolayers of single low molecular weight amphipathic molecules, such as alcohols and carboxylic acids. The free energies of adsorption, Δ G ads ∘ , reveal that the adsorption process is comparable to that occurring in small molecules systems. The linear dependence of Δ G ads ∘ with the number of carbon atoms on the side chain allows estimating the contribution per methylene side group between +0.32 and +0.39 kJ mol −1. On the other hand, the contribution from the polar residue to Δ G ads ∘ ranges between −40.4 and −45.7 kJ mol −1. The dependence of the interfacial tension with temperature suggests that entropy is the driving force factor determining the adsorption process.

Functional L‐Lysine Dendritic Macromolecules as Liver‐Imaging Probes

Liver-imaging probes are prepared through the conjugation of Gd chelates and galactosyl moieties to peptide dendrimers. The dendritic probes possessing highly controlled structures and a single molecular weight have a two-fold increase in T(1) relaxivity to 9.1 x 10(3) (Gd M)(-1) s(-1) compared to Gd-DTPA. No obvious cytotoxicity of this multifunctional dendritic agent is discovered in vitro. The dendrimer bearing galactosyl moieties leads to a much-higher hepatocyte-cell uptake in vitro and provides good signal-intensity enhancement (35%) of mouse liver in vivo especially at 60 min after intravenous injection. In comparison, non-targeting Gd dendrimers provide only an 11% enhancement of imaging contrast at the same time point. Overall, the dendrimers bearing galactosyl moieties may be used as liver-imaging probes.

Digestive Proteolytic Activity in the Sunn Pest,Eurygaster integriceps

The Sunn pest, Eurygaster integriceps Puton (Heteroptera: Scutelleridae), is one of the most important pests of wheat and causes considerable damage to this valuable crop annually. Digestive proteinase activity of adult insects was investigated using general and specific substrates and inhibitors. Proteolytic activity was low when the common conventional substrates, azoalbumin, azocasein and hemoglobin were used to assay salivary glands and midguts. Using the fluorescent casein substrate (BODIPY FL casein), total proteolytic activity was measured at different pH. Maximum proteolytic activity was detected at pH 7 (100%) and 8(65%) which suggested the presence of serine proteinases in the salivary glands. There was no detectable proteolytic activity in midgut extracts. The inhibitors; PMSF (inhibitor of serine proteinases) and TPCK (a specific chymotrypsin inhibitor) showed greater than 50% inhibitory effect on total proteolytic activity, however, TLCK (specific trypsin inhibitor) and E-64(specific cysteine proteinase inhibitor) did not inhibit total proteolytic activity. Using fluorescent specific substrates for serine and cysteine proteinases (Z-Arg-AMC, Z-Arg-Arg-AMC, Z-Arg-Phe-AMC and Suc-Ala-Ala-Pro-Phe-AMZ) revealed the presence of tryptic and chymotryptic activity in the salivary gland extract. Zymogram analysis under non-reducing SDS-PAGE conditions and using the substrate APNE showed at least 8 tryptic and chymotryptic activity bands in salivary gland extracts. A single high molecular weight band with tryptic activity (165 kDa) was detected using the substrate BApNA in a zymogram analysis uisng native-PAGE. Kinetic studies showed a km value of 0.6 mM for this enzyme against the substrate BApNA .The inhibitor TLCK decreased activity of the trypsin-like enzyme up to 73% and almost completely eliminated the only band related to this proteinase in the zymogram. Soybean Kunitz type trypsin inhibitor showed no effect on proteolytic activity of the trypsin-like serine proteinase. In general, the results revealed the presence of chymotrypsin- and trypsin-like serine proteinases in the salivary gland of E. integriceps, and it seems that the major total proteolytic activity is due to chymotrypsin proteinases.

Cellular Effects of Enamel Matrix Derivative Are Associated With Different Molecular Weight Fractions Following Separation by Size‐Exclusion Chromatography

Enamel matrix derivative (EMD) was shown to enhance soft tissue healing and regeneration of the periodontium; however, the mechanisms of this action are unknown. It is assumed that amelogenin, the most abundant protein in EMD, is the protein primarily responsible for the effects of EMD. The purpose of this study was to fractionate EMD and associate its specific cellular effects with different molecular weight fractions following size-exclusion chromatography. Freshly dissolved EMD was fractionated by gel filtration, and forty-five 7-ml fractions were collected, desalted, lyophilized, and resuspended. These fractions were analyzed for their effects on the differentiation of osteoprogenitor cells (C2C12) and the proliferation and differentiation of human microvascular endothelial cells (HMVECs). Alkaline phosphatase activity (C2C12) was measured as a marker for osteogenic differentiation before and after preincubation of the fractions with the bone morphogenetic protein (BMP) decoy receptor, noggin. Angiogenesis (HMVEC) was evaluated as a marker for endothelial cell differentiation. Enzymographic assays used polyacrylamide gels copolymerized with denatured type I collagen to determine gelatinolytic activities in each fraction. EMD fractionated into three major protein peaks following size exclusion chromatography with cross-linked dextran particle matrix. Peak I was associated with the column void volume, whereas peak III eluted near the salt volume. Peak II eluted between these two peaks. Proliferation and angiogenic activities were associated with peaks II and III for the microvascular cells. The differentiation of osteoprogenitor cells, indicated by alkaline phosphatase activity, was induced by EMD components present in peak I and the leading edge of peak II. The additional observation that this differentiation was inhibited by prior treatment of the fractions with noggin suggested the activity was induced by BMP rather than amelogenin or other unknown proteins. Gelatinolytic activities were detected in the early fractions of peaks I and II of gel-fractionated EMD. The cellular activities stimulated by EMD are not associated with a single molecular weight species. The fact that noggin abolishes C2C12 alkaline phosphatase activity suggests that effects on osteoprogenitor cell differentiation are the result of a BMP-like protein(s), whereas effects on proliferation and angiogenesis are associated with lower molecular weight species present in peaks II and III. Finally, unheated EMD displays gelatinolytic activities that are also detectable following size-exclusion separation of its constituents. The masses of these activities were consistent with those reported for latent and active matrix metalloproteinase-20.

Occupational Allergic Contact Dermatitis and Asthma due to a Single Low Molecular Weight Agent

Journal of Occupational HealthVolume 51, Issue 1 p. 91-96 Case StudyFree Access Occupational Allergic Contact Dermatitis and Asthma due to a Single Low Molecular Weight Agent Philippe Moulin, Philippe Moulin EA 3279 Evaluation Hospitalière et Santé Perçue, Université de la Méditerranée and Consultation de Pathologie Professionnelle, Assistance Publique-Hôpitaux de Marseille, FranceSearch for more papers by this authorAntoine Magnan, Antoine Magnan EA 3287, Pathologie Respiratoire Liée à L'environnement, Université de la Méditerranée et Service de Pneumo-allergologie, Hôpital de Ste Marguerite, Université de la Méditerranée, FranceSearch for more papers by this authorMarie-Pascale Lehucher-Michel, Corresponding Author Marie-Pascale Lehucher-Michel marie-pascale.lehucher@ap-hm.fr EA 3279 Evaluation Hospitalière et Santé Perçue, Université de la Méditerranée and Consultation de Pathologie Professionnelle, Assistance Publique-Hôpitaux de Marseille, FranceCorrespondence to: M.P. Lehucher-Michel, Hôpital Timone Adultes, Consultation de Pathologie Professionnelle, Service de Médecine et Santé au travail, 264 rue St Pierre, 13385 Marseille cedex 05, France (e-mail: marie-pascale.lehucher@ap-hm.fr)Search for more papers by this author Philippe Moulin, Philippe Moulin EA 3279 Evaluation Hospitalière et Santé Perçue, Université de la Méditerranée and Consultation de Pathologie Professionnelle, Assistance Publique-Hôpitaux de Marseille, FranceSearch for more papers by this authorAntoine Magnan, Antoine Magnan EA 3287, Pathologie Respiratoire Liée à L'environnement, Université de la Méditerranée et Service de Pneumo-allergologie, Hôpital de Ste Marguerite, Université de la Méditerranée, FranceSearch for more papers by this authorMarie-Pascale Lehucher-Michel, Corresponding Author Marie-Pascale Lehucher-Michel marie-pascale.lehucher@ap-hm.fr EA 3279 Evaluation Hospitalière et Santé Perçue, Université de la Méditerranée and Consultation de Pathologie Professionnelle, Assistance Publique-Hôpitaux de Marseille, FranceCorrespondence to: M.P. Lehucher-Michel, Hôpital Timone Adultes, Consultation de Pathologie Professionnelle, Service de Médecine et Santé au travail, 264 rue St Pierre, 13385 Marseille cedex 05, France (e-mail: marie-pascale.lehucher@ap-hm.fr)Search for more papers by this author First published: 11 February 2009 https://doi.org/10.1539/joh.L7110Citations: 9AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume51, Issue1January 2009Pages 91-96 ReferencesRelatedInformation

Thrombophilia and its impact on pregnancy

In recent years thrombophilia has gained much attention as a risk factor for pregnancy complications. Whereas there is an established correlation between antiphospholipid antibodies and pregnancy loss, data for other risk factors of thrombosis are less well established. Data suggest associations with antithrombin deficiency, hyperhomocysteinemia and also with factor V Leiden, prothrombin G20210A variation and protein S-deficiency. The association of thrombophilia with pre-eclampsia is still under discussion. A limited number of prospective studies did not reveal an increased risk for pregnancy complications in unselected women with thrombosis risk factors. In a single study low molecular weight heparin seemed to have a positive effect on pregnancy outcome after previous single or recurrent abortions. Experience in prevention of pre-eclampsia by administration of prophylactic heparin is very limited. Data on pregnancy complications in women with known heritable thrombophilia or a history of thrombosis are inconsistent as well. These women usually have a favourable pregnancy outcome. In conclusion, thrombophilia screening might be justified in women with pregnancy loss, and treatment with low molecular weight heparin might be considered for those with pregnancy loss and thrombophilia. Further prospective studies and controlled interventional trials are urgently needed.

Binding modes of a dimethyliminopentanone ligand on nickel pre-catalysts toward olefin polymerization

Abstract Nickel complexes prepared using a 4-(2,6-diisopropylphenylimino)-3,3-dimethylpentan-2-one ligand framework are shown. The potassium salt of the ligand is obtained by deprotonation with KH in diethyl ether. Potassium 4-(2,6-diisopropylphenylimino)-3,3-dimethyl-pent-2-en-2-olate can then be reacted with Ni(PMe3)2(η1-CH2Ph)Cl to yield 4-(2,6-diisopropylphenylimino)-3,3-dimethyl-pent-2-en-2-olato-κ1O](η1-CH2Ph)(PMe3)2Ni (1). The potassium salt of the ligand can also be reacted with Ni(PMe3)(η3-CH2Ph)Cl to yield bis(4-(2,6-diisopropylphenylimino)-3,3-dimethyl-pent-2-en-2-olato-κ2N,O](η1-CH2Ph)2Ni2 (2) or 4-(2,6-diisopropylphenylimino)-3,3-dimethyl-pent-2-en-2-olato-κ2N,O](η1-CH2Ph)(PMe3)Ni (3), depending on the reaction conditions. The addition of five equivalents of B(C6F5)3 to 1, 2, or 3 yields catalytically active species for the homopolymerization of ethylene. The polymer products are described by a single molecular weight distribution, consistent with the presence of a single active site.