- Peptide dimethylation: Fragmentation control via distancing the dimethylamino group
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Direct reductive methylation of peptides is a common method for quantitative proteomics. It is an active derivatization technique; with participation of the dimethylamino group, the derivatized peptides preferentially release intense a1 ions. The advantageous generation of a1 ions for quantitative proteomic profiling, however, is not desirable for targeted proteomic quantitation using multiple reaction monitoring mass spectrometry; this mass spectrometric method prefers the derivatizing group to stay with the intact peptide ions and multiple fragments as passive mass tags. This work investigated collisional fragmentation of peptides whose amine groups were derivatized with five linear ω-dimethylamino acids, from 2-(dimethylamino)-acetic acid to 6-(dimethylamino)-hexanoic acid. Tandem mass spectra of the derivatized tryptic peptides revealed different preferential breakdown pathways. Together with energy resolved mass spectrometry, it was found that shutting down the active participation of the terminal dimethylamino group in fragmentation of derivatized peptides is possible. However, it took a separation of five methylene groups between the terminal dimethylamino group and the amide formed upon peptide derivatization. For the first time, the gas-phase fragmentation of peptides derivatized with linear ω-dimethylamino acids of systematically increasing alkyl chain lengths is reported.
- McShane, Adam J.,Shen, Yuanyuan,Castillo, Mary Joan,Yao, Xudong
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Read Online
- Lipids and compositions for the delivery of therapeutics
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The present invention provides lipids that are advantageously used in lipid particles for the in vivo delivery of therapeutic agents to cells. In particular, the invention formula (I) provides lipids having the following structure XXXIII wherein: R1 and R2 are each independently for each occurrence optionally substituted C10-C30 alkyl, optionally substituted C10-C30 alkenyl, optionally substituted C10-C30 alkynyl, optionally substituted C10-C30 acyl, or -linker-ligand; R3 is H, optionally substituted C1-C10 alkyl, optionally substituted C2-C10 alkenyl, optionally substituted C2-C10 alkynyl, alky lhetro cycle, alkylphosphate, alkylphosphorothioate, alkylphosphorodithioate, alkylphosphonates, alkylamines, hydroxyalkyls, ω-aminoalkyls, ω-(substituted)aminoalkyls, ω-phosphoalkyls, ω-thiophosphoalkyls, optionally substituted polyethylene glycol (PEG, mw 100-40K), optionally substituted mPEG (mw 120-40K), heteroaryl, heterocycle, or linker-ligand; and E is C(O)O or OC(O).
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Page/Page column 124; 125
(2015/12/04)
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- Maximizing the potency of siRNA lipid nanoparticles for hepatic gene silencing in vivo
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Special (lipid) delivery: The role of the ionizable lipid pKa in the in?vivo delivery of siRNA by lipid nanoparticles has been studied with a large number of head group modifications to the lipids. A tight correlation between the lipid pKa?value and silencing of the mouse FVII gene (FVII ED50) was found, with an optimal pKa range of 6.2-6.5 (see graph). The most potent cationic lipid from this study has ED50 levels around 0.005?mg?kg?1 in mice and less than 0.03?mg?kg?1 in non-human primates.
- Jayaraman, Muthusamy,Ansell, Steven M.,Mui, Barbara L.,Tam, Ying K.,Chen, Jianxin,Du, Xinyao,Butler, David,Eltepu, Laxman,Matsuda, Shigeo,Narayanannair, Jayaprakash K.,Rajeev, Kallanthottathil G.,Hafez, Ismail M.,Akinc, Akin,Maier, Martin A.,Tracy, Mark A.,Cullis, Pieter R.,Madden, Thomas D.,Manoharan, Muthiah,Hope, Michael J.
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supporting information; experimental part
p. 8529 - 8533
(2012/10/18)
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- Powerful protein binders from designed polypeptides and small organic moleculesa-A general concept for protein recognition
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High-affinity binders for the C-reactive protein (CRP), with dissociation constants in the pM to nM range and selectivities in human serum comparable to those of antibodies, were obtained by conjugation of 16 designed polypeptides to phosphocholine, a sma
- Tegler, Lotta T.,Nonglaton, Guillaume,Buettner, Frank,Caldwell, Karin,Christopeit, Tony,Danielson, U. Helena,Fromell, Karin,Gossas, Thomas,Larsson, Anders,Longati, Paola,Norberg, Thomas,Ramapanicker, Ramesh,Rydberg, Johan,Baltzer, Lars
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supporting information; experimental part
p. 1823 - 1827
(2011/04/16)
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- Esters and amides of hexanoic acid substituted with tertiary amino group in terminal position and their activity as transdermal permeation enhancers
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Series of alkyl esters of 6-(diethylamino)-, 6-(pyrrolidin-1-yl)-, 6-(piperidin-1-yl) and 6-(m orpholin-4-yl)hexanoic acids and alky lamides of 6-(dimethylamino)-, 6-(piperidin-1-y l) and 6-(morpholin-4-yl)hexanoic acids, co n-taining 8-12 c arbon ato ms in the alky l chai n, were prepared by m ethods of classical organi c sy nthesis. The appr opriate secondary a mine wa s alky lated with ethyl 6-bromohexanoate to give ester of ω-substituted hexanoic acid, except of ethy l 6-(di methylamino)hexanoate (1), which wa s pr epared by Esch-weiler-Clarke methylation of 6-a minohexanoic acid followe d by direct est erification with ethanol. The resulted esters of ω-substituted hexanoi c aci ds underwent dire ct transest erification with long chain alka nols to y ield the desired amino esters, or they were treated with long-chain alkylamines to prepare secondary a mides of the appropriate heterocy clic hexa noic a cids. These products were in vitro tested on their activity as transdermal permeation enhancers on the strip s of the excised hu man skin with theophylline as the model permeant. The activity was evaluated u sing para meter enh ancement ratio (ER), defined as the ratio between the overall am ount of the per meant pa ssing through the skin with the t ested enha ncer an d that witho ut tested substance. Decyl 6-(pyrrolidin-1-yl)hexanoate (9) with ER = 30 showed the high est activity. The enhancing effect s of the esters were generally better than those of the amides.
- Farsa, Oldrich,Dolezal, Pavel,Hrabalek, Alexandr
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scheme or table
p. 595 - 603
(2010/08/22)
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- Collision-induced loss of AgH from Ag+ adducts of alkylamines, aminocarboxylic acids and alkyl benzyl ethers leads exclusively to thermodynamically favored product ions
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The loss of AgH from [M + Ag]+ precursor ions of tertiary amines, aminocarboxylic acids and aryl alkyl ethers is examined by deuterium labeling combined with collision activation (CA) dissociation experiments. It was possible to demonstrate tha
- Schaefer, Mathias,Dreiocker, Frank,Budzikiewicz, Herbert
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experimental part
p. 278 - 284
(2009/07/11)
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- ORGANIC ACTIVATOR
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This invention relates to organic activators having the formula (I), wherein Z is a charge equalizing ion and one or more of the moieties R1, R2, R3, R4 and R55 are modified such that the one or more
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- Esters of 6-dimethylaminohexanoic acid as skin penetration enhancers
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We prepared a series of five esters of 6-dimethylaminohexanoic acid, and characterised the compounds by their NMR and IR spectra. Their ability to function as transdermal penetration enhancers was subsequently evaluated using excised human skin as a membrane, modified Franz diffusion cells, and theophylline as a model permeant. The penetration - enhancing efficiency of esters 1-5 was studied in the donor media of propylene glycol and isopropyl myristate, and expressed as the corresponding enhancement factors (EF). All the esters increased the penetration of theophylline through the skin. The enhancement factor for the most active substance, undecyl 6-dimethylaminohexanoate, was 118.5 (± 19) from propylene glycol.
- Hrabalek,Dolezal,Farsa,Sklubalova,Kunes
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p. 759 - 761
(2007/10/03)
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- Multiple-substituted bleach activators
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Bleaching compositions, laundry and automatic dishwashing detergent compositions comprising multiple-substituted bleach activators which have at least one quaternary nitrogen atom, are provided. More specifically, the invention relates to compositions which provide enhanced cleaning/bleaching benefits though the selection of multiple-substituted quaternary bleach activators having specific leaving groups with a conjugate acid aqueous pKa above 13 and with advantageous ratios of rate of perhydrolysis to rate of hydrolysis and of rate of perhydrolysis to rate of diacylperoxide production. Included are preferred activator compounds and methods for washing fabrics, hard surfaces, and tableware using the activators.
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